That bit you always heard about not judging a book by its cover? It's good advice. Case in point: the 2011 Volkswagen GTI you see here. That's right, the sensible-looking four-door family car in Carbon Steel Grey. The one that just blew past you like a Fourth of July bottle rocket.

That's exactly the effect Ryan Jacobs envisioned when he first started improving his '11 GTI. After years behind the wheel of several tweaked-up JDM rides, Ryan crossed borders for something from the Old Country. A practical daily driver was the requirement, but he wasn't quite ready to give up the performance he was accustomed to. Like so many before him, he soon found himself the owner of a brand-new GTI.

See all 25 photos

Right out of the box, the MK6 Volkswagen GTI is a pretty ideal mix of performance and practicality, but Ryan knew there was more to be had from its turbocharged 2.0-liter engine and sophisticated chassis. Almost immediately, he got to work changing out factory parts with carefully curated upgrades from the aftermarket with the ultimate goal of creating the perfect GTI.

Ryan has spent virtually every day of the last four years in search of the right upgrades to make his GTI the ideal balance of daily driver and track beast. In just about every corner of the car, he has gone through numerous iterations in search of "just right." The parts he's tried and discarded would be an enviable list for most of us, but his dedication—or maybe more accurately, his obsession to perfection—shows in the final product. You want proof? Search any of the big VW forums for his build threads, where he posts under the handle HYDE16. The man is pathological.

See all 25 photos

The logical starting point for adding power to a modern turbocharged VW is, naturally, engine software. Redline Speed Worx flashed the ECU with APR's multi-program software package, consisting of stock, 91-octane, 93-octane, and 100-octane race gas settings. This was later upgraded to play along with new K04 turbo hardware and a front-mount intercooler, also from APR.

To handle the heavier breathing, Ryan replaced the factory airbox with an open intake system from Unitronic and upgraded the standard MAP (manifold absolute pressure) sensor with a high-performance factory unit from the Golf R. He then turned to Neuspeed for throttle body and turbo discharge pipes to keep things moving smoothly through this typical bottleneck.

See all 25 photos

Inside the K04 turbo, SoCalPorting worked its magic with a full port and polish on the turbocharger and exhaust manifold to clean up the flow of hot gases. To keep the turbo performing at its peak, Ryan ditched the factory diverter valve in favor of a heartier DV+ unit from GoFastBits, which sits on a relocated mount from Unitronic. All said and done, the engine's fiery-hot breath leaves the GTI through a custom 3-inch exhaust from SPM.

The ignition system was upgraded with high-performance coil packs from Ignition Projects firing NGK 8-series iridium plugs. To ensure reliable power supply under more demanding conditions, a compact, lightweight GU1R lithium battery from Braille replaces the conventional lead-acid anchor, removing nearly 40 pounds from the front end in the process.

See all 25 photos

In this state of tune, the 2.0T TSI engine jumped from 207 hp and 220 lb-ft of torque to 375 hp and 402 lb-ft in its 100-octane race gas program. Ryan uses an Aquamist HFS-4 water/methanol injection system from Howerton Engineering to achieve 100-octane performance from 93-octane pump gas. Four jets individually feed each cylinder through the intake plenum with a fifth jet to cool the throttle body's intake charge, all fed by a Coolingmist 2.3 Gallon All in One Pro Tank that is cleanly integrated into the rear cargo area.

With so much invested in engine upgrades, Ryan reflected on another old adage, the one about an ounce of prevention being worth a pound of cure. Starting with the cooling system, he ditched the factory radiator and its failure-prone plastic end caps for a high-performance all-aluminum piece from Tyrolsport, while a Dimple magnetic drain oil drain plug pulls out any free-range ferrous material from the lubrication system. Heat-deflecting Lava Turbo Blankets from PTP wrap the downpipe and turbocharger to shield the engine bay from excessive temps, with a matching set of firewall and underhood blankets protecting vital electronic components while soaking up direct injection noise.

See all 25 photos

A South Bend Stage 3 clutch disk delivers power to a beefed-up six-speed factory gearbox built by Redline Speed Worx. A DieselGeek short shift kit, enhanced by TyrolSport solid shifter bracket bushings, acts on steel shift forks from USP Motorsports. A limited-slip diff from Peloquin negotiates torque between the left and right Driveshaft Shop level-2.9 axles. A Stage 1 upper motor mount from Black Forest Industries and a stiffer lower motor mount from HPA keep the engine and trans in place when the torque starts flowing.

Behind the perpetually clean 18x8 VMR V705 five-spoke alloys lives a meticulously sorted brake setup. The fronts feature four-piston StopTech ST-40 calipers on 328mm two-piece slotted rotors, while the rear calipers are upgraded factory units from a Mk V R32 acting on 310mm StopTech slotted rotors. Ryan had the calipers powdercoated black for a clean, subtle appearance and uses Hyde's Serum, a product he developed himself, to keep rust from forming on the steel brake rotors after the car is washed. StopTech stainless steel lines and a TyrolSport master cylinder brace ensure the forces applied at the pedal translate into rock-solid braking performance at the discs, no doubt helped by the sticky 225/40-18 Michelin SuperSport tires.

See all 25 photos

All about the go and less about the show, it should come as no surprise that Ryan chose function over "stance" when it came to the suspension as well, foregoing airbags for old-school steel. A coilover kit from ST Suspensions replaces the factory springs, shock, and struts, aided by H&R sway bars at both axles. The steel front control arms have been replaced with SuperPro alloy units with upgraded bushings. The rear trailing arm bushings and sway bar endlinks are also upgrades courtesy of Whiteline.

With all the added stiffness in the suspension components, the GTI's unibody was in need of its own reinforcements. The rear body section is stiffened with a carbon-fiber hatch brace from TyrolSport, and the front and rear suspension subframes are more solidly connected to the body with TyrolSport's DeadSet Rigid Collar kits.

See all 25 photos

Despite all the work beneath the skin, Ryan has intentionally kept the outward appearance of his GTI decidedly low-key. No sense drawing unwanted attention, after all. Carbon Steel Grey, it turns out, is the perfect canvas for a sleeper, the car's menacing presence its only real giveaway. Upgrades on the outside are largely limited to bits and pieces from the VW parts bin. Golf R taillights and a European Golf Highline grille give the GTI a simple, purposeful look. To go with the taillights, all the other exterior running lights are equipped with LEDs. The mirror caps, front spoiler, and rear valance are color-matched to the wheels for an understated accent, a tinted rear reflector matches the taillights, and the front-side markers were color-matched to the car to finish off the effect.

The cockpit is equally clean and free of unnecessary embellishments. An AWE boost gauge in the left-side dash vent delivers vital stats on the engine's inner workings alongside a column-mounted gauge for the Aquamist system. LEDs illuminate the cockpit. With all the heavy-duty hardware he's installed, it might be fair to assume Ryan has overworked a perfectly good GTI. But you'd be wrong. From the driver seat, the car retains all its original charms, but everything is now sharper, more precise, and much more effective. Power, braking, cornering. All of it is just about as perfect as a front-drive car can ever hope to be.

See all 25 photos

The engine is a powerhouse that requires thoughtful application of the right pedal to manage responsibly. Needless to say, it will freely spin its front tires at launch. But what's surprising is how easily a full-throttle drop from cruising speed in Third or Fourth gear can just as easily deliver the same effect. Moderation is the key to a smooth drive with so much power in reserve.

Working the gears in Ryan's GTI is a rare pleasure as well, since all the usual freeplay and slop have been eliminated from the cable-operated linkage. Instead, it's a smooth, precise experience that feels more akin to a longitudinally mounted rear-drive gearbox with stick acting directly on the internals. The clutch is firm and precise as well, yet requires little in the way of added effort. Likewise, everything about the brakes is firm and exacting in its performance.

Perhaps most surprising is the level of refinement this odd menagerie of parts delivers. The suspension, for instance, is damn-near magical in its ability to mask road imperfections while simultaneously eliminating body roll when the road goes all twisty.

See all 25 photos

There's none of the expected bunny-hopping over pavement seams, no bump-steer mid-corner. The combination of a stiff chassis with relatively soft suspension components pays dividends in the real world.

The same goes for the exhaust. Despite a deep howl at start-up, the pipes are extremely mellow once the engine is warmed up. From outside the car, there's no denying it's a performance beast, its deep bass song resonating proudly at full stomp. Inside, however, there's a surprising absence of "cruising boom," that tendency large-bore exhausts often have for creating an annoying resonant frequency when rolling along at fairly low engine speeds. You can actually converse at normal speaking levels while cruising in Ryan's car.

Most enthusiasts would look at Ryan's car and see a finished project. Heck, most people would have considered this car finished long before this level, but as you may have guessed, there are still plans. Ryan intends to do a full engine build with components from Integrated Engineering. Stronger rods and pistons will get the squeeze from a twin-scroll turbo kit. He has visions of 500 hp, which makes me wonder if that will be the tipping point that turns this beautifully sorted dual-purpose build into a full-time track monster.

See all 25 photos

Owner's Choice

I asked Ryan about some of his favorite components he's used on the GTI. He has obviously researched and tested these parts at length, so he knows what works and what doesn't. He was nice enough to list a few of his car's greatest hits in order of cost.

See all 25 photos

1. TyrolSport—DeadSet Rigid Subframe Collar Kit: A simple fix to the "subframe clunk" on several newer VW models. The kit consists of machined brass collars and ARP bolts that precisely locate the car's front subframe, eliminating any slop or movement. It provides a more solid feel and eliminates the banging sounds. Retail: $225

See all 25 photos

2. Diesel Geek—Sigma 6 Short Shift Kit: It may look like overkill, but the chunky billet aluminum pieces in the Diesel Geek shifter remove all the slop and flex in the factory setup. Plastic rod ends are replaced with Teflon-lined steel spherical bearings, and the remaining plastic in the slider has been replaced with a higher strength structural plastic. Retail: $195

See all 25 photos

3. Aquamist—HSF4 Water/Methanol Injection Kit: While most water/meth kits are simple on or off and triggered by boost pressure, the HSF4 uses a combination of injector pule width, fuel line pressure, and boost to determine when and how much to spray. It may not be a cheap modification, but when you look at the price of larger intercoolers and the price of 100-octane gas, this starts to make more sense. Retail: $885

Engine/Engine Compartment: APR 2.0T TSI K04 Conversion/ECU flash and intercooler, Aquamist Water/Alcohol Injection, Unitronic cold air intake system, GFB T9351 DV+ diverter valve kit, Neuspeed HI FLO K04 turbo discharge pipe, VW Golf R 3-bar MAP sensor, SoCalPorting turbo and exhaust manifold port & polish, SPM 3" custom turbo-back exhaust, TyrolSport aluminum radiator, 034 Motorsport oil catch can, Black Forest Industries Stage 1 engine mount, HPA 75-durometer (red) lower engine mount, Braille GU1R Green Lite lithium battery combo, PTP Turbo Lava turbo blanket, downpipe heat wrap and firewall blanket

APR 2.0T TSI K04 Conversion/ECU flash and intercooler, Aquamist Water/Alcohol Injection, Unitronic cold air intake system, GFB T9351 DV+ diverter valve kit, Neuspeed HI FLO K04 turbo discharge pipe, VW Golf R 3-bar MAP sensor, SoCalPorting turbo and exhaust manifold port & polish, SPM 3" custom turbo-back exhaust, TyrolSport aluminum radiator, 034 Motorsport oil catch can, Black Forest Industries Stage 1 engine mount, HPA 75-durometer (red) lower engine mount, Braille GU1R Green Lite lithium battery combo, PTP Turbo Lava turbo blanket, downpipe heat wrap and firewall blanket Transmission/Drivetrain: South Bend Stage 3 TSI clutch disc, BMC short-throw clutch stop, DieselGeek Sigma 6 short shift kit, TyrolSport solid shifter bracket bushing kit, Peloquin limited-slip differential, Driveshaft Shop level 2.9 axle assemblies

South Bend Stage 3 TSI clutch disc, BMC short-throw clutch stop, DieselGeek Sigma 6 short shift kit, TyrolSport solid shifter bracket bushing kit, Peloquin limited-slip differential, Driveshaft Shop level 2.9 axle assemblies Chassis/Suspension: ST Suspensions Coilover Kit, Audi TT strut mounts, H&R 26mm front/24 mm rear sway bar, SuperPro Performance control arm kit, Whiteline rear trailing arm front bushings, TyrolSport DeadSet rigid front and rear subframe collar kits

ST Suspensions Coilover Kit, Audi TT strut mounts, H&R 26mm front/24 mm rear sway bar, SuperPro Performance control arm kit, Whiteline rear trailing arm front bushings, TyrolSport DeadSet rigid front and rear subframe collar kits Brakes: StopTech ST-40 328mm 4-piston front brake kit with slotted rotors, StopTech 310mm rear slotted brake rotors, VW Mk V R32 rear brake calipers, TyrolSport master cylinder brace

StopTech ST-40 328mm 4-piston front brake kit with slotted rotors, StopTech 310mm rear slotted brake rotors, VW Mk V R32 rear brake calipers, TyrolSport master cylinder brace Wheels/Tires: 19 x 8 inch VMR V705 Alloy Wheels, 225/40-18 Michelin Pilot Super Sport tires

19 x 8 inch VMR V705 Alloy Wheels, 225/40-18 Michelin Pilot Super Sport tires Exterior: VW Euro "Highline" front grille, Golf R LED taillights

VW Euro "Highline" front grille, Golf R LED taillights Interior: AWE vent-mount boost gauge, Stinger Roadkill door and truck sound deadening kits

This story originally appeared in European Car.