This 1999 BMW 528iT was ordered new through BMW’s Individual program finished in Mojave Brown Metallic with the seller acquiring it four years ago at around 150k miles. 10k miles ago, this wagon was transformed with a modified 7-liter GM LSx 427 iron-block engine mated to a T56 Tremec Magnum 6-speed manual transmission producing a dyno-proven 493 horsepower and 467 lb-ft. of torque at the wheels. In addition to extensive mechanical work throughout, a near-complete E39 M5 Nappa Heritage Caramel leather interior was swapped in and the exterior was freshened up as detailed below. The mechanical conversion was completed to a high standard with the seller stating that about $35k in parts alone were utilized for the build. It is now offered with a fully documented 36-page build thread and a clean Virginia title.

Outside, the car appears mostly stock with modifications including tinted windows, Umintza front and rear aftermarket bumpers, custom headlights with Orion V2 angel eyes and Nissan Murano projectors, and Celis European tail lights. Mojave Brown Metallic paint suits the low-key appearance nicely with several dings, scratches, and flaws noted by the seller along with slightly-off bumper fit detailed in the photo gallery below.

Years ago, this wagon was involved in a minor front-end collision that is noted on the Carfax, and several dents in the hood and passenger front fender remain. It was built to be a driver, so the seller elected to leave the paint as-is in order to enjoy using the vehicle worry-free. Nevertheless, the seller notes that the paint still presents nicely with two small rust spots present on the tailgate that have reportedly not spread during his ownership.

This wagon sits nicely hunkered down thanks to a custom suspension system utilizing Fortune Auto M5 500 front coilovers with camber plates and rear 510 shocks with coilover perches. The rear units were just re-valved with new internals and then dyno-tested and calibrated by the lead technician at Fortune Auto. Thayer Motorsports rear adjustable control arms with full camber/toe adjustability and a Shroeder stock car 1.25” front sway bar help tighten things up.

A custom-built M5 210mm differential with E46 M3 3.62 ring/pinion gear, new seals, and machine work for triple clutches allow for 40% lock and help to keep the car planted. It will pull straight as an arrow even when spinning the tires according to the seller. Finally, a reinforced differential mount, new OEM differential and trailing arm bushings, and Powerflex black polyurethane sub-frame bushings round out the comprehensive setup.

Stopping power is handled with an M5 Brembo GT front and rear Big Brake Kit with 355×32 mm front and 335×28 mm rear two-piece rotors and four-piston calipers. Recently, new front rotors were fitted along with four new brake pads. 19″ Apex Arc-8 wheels are wrapped in Continental DW 245/35 tires up front and Continental SportContact 285/30 tires in the rear. The seller notes that the rear tires will rub with multiple passengers on board and have a few sidewall cuts present. The next owner should install 275 width tires to remedy the issue. The seller notes that the brake-warning lamp is illuminated due to the upgraded braking system and potential bidders should be aware that the car does not have traction control.

Inside, E39 M5 Nappa Heritage Caramel leather front seats and door panels were swapped in from a 50k-mile car along with the corresponding dashboard and center console. The black factory rear seat is still fitted and an M5 unit will be included with the sale. New black carpets, an alcantara-covered headliner and pillars and rare, crack-free OEM Birch Anthracite trim round out the look. The leather appears to be in clean condition throughout with typical wear on the driver’s outer bolster, thigh support, and door panel.

Other added appointments include an OEM M5 steering wheel, Pioneer 7″ head-unit, and Alpine speakers/amplifier. All instrumentation is said to be in good order except for the digital fuel economy display. All warning lamps are fully functioning since the OBDII port for the Cadillac CTS-V accessory kit and harness is in the BMW OEM location. The seller mentions that the instrument cluster displays a “tamper dot” since a new light control module that could not be paired with the ECU was used. The A/C was just recharged and reportedly blows cold. The odometer shows around 160k total chassis miles.

Under the hood lurks a modified 7-liter GM LSx 427 iron-block engine that was rebuilt 2k miles ago with the following specifications using new and existing parts:

E67 standalone ECU

Titanium rods and intake valves

Sodium-filled exhaust valves

Heat-treated and polished crankshaft

LS7 heads and intake manifold

New GM race lifters and a Tick performance camshaft

Honed cylinders

New rod and main bearings

New ARP rod and main bolts

New oil pump

All-new gaskets and seals

New timing chain

Custom stainless steel expansion tank

Dual GM Malibu fans

The motor was dyno tuned and made 493 horsepower and 467 lb-ft. of torque at the wheels with a photo showing the results displayed in the gallery below. The seller notes that the auxiliary fan for the A/C is currently inoperable and he is actively working to fix the issue. Other than that, the engine is said to deliver strong power and is well-matched to the T56 Tremec Magnum 6-speed manual transmission, which is paired to a twin-disc Corvette ZR1 clutch. A video of one of the dyno pulls is shown below:

Underneath, upgraded components include an Autokraft oil pan, long tube headers, a custom dual stainless 3” header-back exhaust, twin Borla XR-1 mufflers, and twin high flow catalytic converters. Custom engine and transmission mounts, an M5 two-piece driveshaft with GM slip yoke, new CSB, and M5 axles round things out. The exhaust note is purposeful to say the least:

The seller reports that this wagon is incredibly fun to drive with instant torque and handling characteristics to match. It has been weighed at just over 4,000 lbs. and is within 1% from 50/50 front/rear and left/right distribution. No expense has been spared in the mechanical preparation of this wagon and interested parties are encouraged to watch the additional video below: