With mainstream automakers offering luxury-laden trims while prestige car brands attempt to democratize luxury, we organized four comparison tests to see who does posh better for a capped price of $40,000.

We ask our vehicles to be good for multiple uses, but few are asked to do such disparate duties as luxury sports cars. They need to ride nicely but handle well. They need to have quiet interiors but aggressive exhaust notes. They need to be light and nimble but come with fancy materials and loads of features that add weight. Everything ends up being some kind of trade-off.

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The more money you can throw at the problem, the fewer compromises you need to make. But this test is specifically about not throwing money at the problem. With a $40,000 price cap, we find ourselves with the keys to a 2018 Cadillac ATS 2.0T coupe and a 2018 Ford Mustang EcoBoost, both just squeaking in as tested. Although both cars can be had with a manual transmission, we opted for automatics because this is a consumer test, and the vast majority choose automatics.

Before we get into this, though, let's usher a couple elephants out of the room. Yes, for this money, you could get a Mustang with a V-8. Besides being wildly unfair pitting a V-8 against a turbo-four, speccing the bigger engine would mean we couldn't afford many luxury features with the Mustang, and that's the whole point of this comparison. Meanwhile, most folks don't associate Cadillac with "sporty" until you get to the V-spec models. But the ATS is positioned as a sporty coupe. And that means going up against cars such as the Mustang. We eagerly anticipate your outraged emails.

As configured, these two cars are pretty similar. The Cadillac is slightly smaller and notably lighter (nearly 300 pounds) with a tighter front seat and smaller trunk. It even rings up cheaper at $39,490 to the Ford's $39,880. The Ford fights back with a more powerful engine and subsequently a better power-to-weight ratio, yet it still manages to match the Cadillac's fuel economy.

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In standardized testing, though, it's anything but a draw. The stronger, heavier Mustang is quicker to 60 mph and through the quarter mile, though the ATS nearly caught up by the end of the drag. The Mustang stops 8 feet shorter from 60 mph, pulls higher average g on the skidpad, and laps our figure eight test quicker and at higher average g. Also, the Mustang sounds better.

Although the raw horsepower and torque of the EcoBoost engine can be credited for the speed advantage, it's the tires that make the difference in most of the testing. The Cadillac—with zero window sticker options to keep it price competitive—rides on Continental ProContact all-seasons. The Mustang, meanwhile, is equipped with the EcoBoost Performance package, which among other things buys you a limited-slip differential and Pirelli P Zero summer performance tires.

The tire discrepancy made itself known during our evaluation. The Cadillac has a wonderful chassis, but it doesn't work with these tires. Attempting to drive aggressively gets you a handful of understeer as the tires quickly cry uncle. OK, slow in, fast out, right? Nope. The tires can't put the power down, either, so you get draconian traction control intervention. I generally don't turn off any of the nannies while on the street, but with the Cadillac's traction control, I made an exception. It makes the car drivable on a good road, and you still are protected by the stability control safety net. Budget an extra grand for better tires to make this car handle as it should.

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Although the Mustang has vastly superior front-end grip, it's not perfect. Power tends to come on like a hammer, especially in the various Sport modes, and it'll easily overwhelm the rear tires and rouse the stability control. Mustangs like to snap oversteer and need to be driven with finesse, and the little-engine model is no exception. Drive it like you stole it, and it's like trying to wheel a classic Mustang in Bullitt. Learn its bad habits, and on a mountain road it'll leave the ATS for dead. In everyday driving, there's no denying the Ford feels quicker and sportier than the Cadillac.

The Mustang's all-new 10-speed automatic transmission also contributes to its performance. It was brilliant on the road. The shifts were smoother and quicker than the Cadillac's, both up and down, and it always knew what gear to be in. In Sport mode, it behaved so well that it made the paddle shifters superfluous.

The eight-speed automatic in the ATS was the opposite. It shifts smoothly but wants to be in eighth gear regardless of drive mode. You need to use the paddles to drive the Cadillac quickly, but even they respond slowly.

Despite the Mustang outperforming the ATS, we could never find an ideal setup. The damper settings are permanently tied to the multiple-choice driving modes, and the steering weight is adjustable only in some modes. As a result, we ended up in Sport mode—where the dampers are too soft but the steering isn't ridiculously heavy and the throttle isn't hair-trigger. Even the customizable My mode wouldn't let us mix and match settings the way we wanted.

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Still, the Mustang, as equipped, is clearly the better sports car. But which is the better luxury car? Here, the race tightens. The Mustang registers the loudest interior of all eight cars in this comparison, but the Cadillac's is the second loudest. Likewise, the Mustang, despite its optional MagneRide active dampers, rides more like a sports car than the luxury-oriented Cadillac.

Despite that, we still prefer the Mustang's cabin. We admire Cadillac's commitment to "cut and sewn" materials, but we take issue with the materials chosen to cut and sew. The sheets of vinyl stitched to the dash call quite a bit of attention to themselves, and not the good kind. If you're not going to wrap the dash in leather or suede, don't bother. The Mustang's soft-touch dash is plastic, but it doesn't look like it's trying too hard. We're calling a draw on the Cadillac's plastic wood trim versus the Ford's dull gray plastic.

Elsewhere on the dash, we come to a tale of two infotainment systems. Both have long suffered software development issues, and both seem to have finally gotten it right. We find Ford's Sync 3 more intuitive than Cadillac's CUE, but the latter looks more hip and modern. The Cadillac's lack of navigation is to be expected at this price and is mitigated by Apple CarPlay and Android Auto integration. (Ford provides both, as well.) Unfortunately, there's no getting around the fact that CUE's entirely touch-sensitive interface is housed in a waterfall of black plastic cascading down the dashboard while the Mustang gets cool metal toggle switches and knurled knobs.

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Likewise, the '90s-inspired gauges in the ATS look dated next to the Mustang's futuristic-looking digital gauges. Although Ford's interface might look better, with layer upon layer of menus and multiple buttons scattered around the steering wheel, it's a lot less intuitive than the Cadillac's.

It's a similar story when you consider the seats you'll be sitting in. The Cadillac's imitation leather is plenty convincing, but even then you don't get enough of it, thanks to some cloth patches substituted in places Cadillac thinks you won't notice. The Ford's seats are sportier with leather and contrast stitching, though we're split on which is more comfortable. Not up for debate: At this price point, the Mustang's seats are both heated and cooled; the Cadillac's

are neither.

The extra room in the front of the Ford is appreciated, but it makes the rear seats less useful. To be fair, the Cadillac's rear seats are only slightly more utile. Kids only in the back for both. Don't bring too much stuff with you, either, because neither car has a big trunk. The ATS has a larger opening to get your bags through, but the Mustang has a larger and more usable trunk because it doesn't have the ATS' intruding wheelwells.

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Then there are the money matters. Nearly identical as-tested prices mean nearly identical financing costs, and the same goes for fuel economy. Of all eight cars in this test, the Mustang is the most expensive vehicle to insure, but the ATS is second-worst by a slim margin. Maintaining the Cadillac is more expensive, but the Ford's repair costs are steep. The real difference, and it's a doozy, is in depreciation. The Cadillac has the worst depreciation in this test; the Ford comes in at the average.

So it went and so it goes with these two. Neither is our ideal four-seat sports car, nor is either a standout luxury car. With two equally priced cars, the decision then comes down to which we'd rather drive. With better performance, a better driving experience, far more features, a nicer cabin, and a cheaper cost of ownership, the answer is inescapably Mustang.

Although Ford won this shootout fairly comprehensively, you might have your own priorities as far as practical wants and needs. So for those still on the fence …

Get the Ford if you:

1 Like a turbo-four with guts

2 Expect your sporty car to handle

3 Like lots of features with your purchase

4 Like direct steering feel

Get the Cadillac if you:

1 Can't picture spending $40K on a Mustang

2 Like a better ride

3 Like smoother shifts

4 Are willing to swap out for better tires

Read our closing thoughts on all four luxury-versus-mainstream comparison tests here!

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See all 56 photos

See all 56 photos

Read our other comparison tests right here!

2018 Cadillac ATS Coupe 2.0T 2018 Ford Mustang Coupe (EcoBoost) DRIVETRAIN LAYOUT Front-engine, RWD Front-engine, RWD ENGINE TYPE Turbocharged I-4, alum block/head Turbocharged I-4, alum block/head VALVETRAIN DOHC, 4 valves/cyl DOHC, 4 valves/cyl DISPLACEMENT 121.9 cu in/1,998 cc 138.0 cu in/2,261 cc COMPRESSION RATIO 9.5:1 9.5:1 POWER (SAE NET) 272 hp @ 5,500 rpm* 310 hp @ 5,500 rpm†† TORQUE (SAE NET) 295 lb-ft @ 3,000 rpm* 350 lb-ft @ 3,000 rpm†† REDLINE 7,000 rpm 6,500 rpm WEIGHT TO POWER 12.6 lb/hp 12.0 lb/hp TRANSMISSION 8-speed automatic 10-speed automatic AXLE/FINAL-DRIVE RATIO 3.27:1/2.16:1 3.55:1/2.26:1 SUSPENSION, FRONT; REAR Struts, coil springs, anti-roll bar; multilink, coil springs, anti-roll bar Struts, coil springs, adj shocks, anti-roll bar; multilink, coil springs, adj shocks, anti-roll bar STEERING RATIO 16.8:1 16.0:1 TURNS LOCK-TO-LOCK 3.0 2.5 BRAKES, F; R 12.6-in vented disc; 12.4-in vented disc, ABS 13.9-in vented disc; 13.0-in vented disc, ABS WHEELS 8.0 x 18-in; 9.0 x 18-in, forged aluminum 9.0 x 19-in forged aluminum TIRES 225/40R18 88V; 255/35R18 90V Continental ProContact RS SSR (M+S) 255/40R19 96Y Pirelli P Zero DIMENSIONS WHEELBASE 109.3 in 107.1 in TRACK, F/R 60.3/61.7 in 62.4/65.1 in LENGTH x WIDTH x HEIGHT 183.6 x 72.5 x 54.8 in 188.5 x 75.4 x 54.3 in TURNING CIRCLE 36.4 ft 40.0 ft CURB WEIGHT 3,417 lb 3,709 lb WEIGHT DIST, F/R 51/49% 54/46% SEATING CAPACITY 4 4 HEADROOM, F/R 37.6/35.1 in 37.6/34.8 in LEGROOM, F/R 42.3/33.5 in 45.1/29.0 in SHOULDER ROOM, F/R 54.1/51.1 in 56.3/52.2 in CARGO VOLUME 10.4 cu ft 13.5 cu ft TEST DATA ACCELERATION TO MPH 0-30 1.8 sec 2.0 sec 0-30 2.8 2.8 0-50 4.0 3.8 0-60 5.6 5.3 0-70 7.1 6.8 0-80 9.2 8.6 0-90 11.4 11.2 0-100 14.4 15.0 PASSING, 45-65 MPH 2.9 2.6 QUARTER MILE 14.0 sec @ 98.6 mph 13.9 sec @ 97.2 mph BRAKING, 60-0 MPH 114 ft 106 ft LATERAL ACCELERATION 0.91 g (avg) 0.96 g (avg) MT FIGURE EIGHT 25.6 sec @ 0.71 g (avg) 25.1 sec @ 0.75 g (avg) TOP-GEAR REVS @ 60 MPH 1,500 rpm 1,700 rpm SOUND LEVEL† @ FULL THROTTLE 35.0 sones (max) 43.7 sones (max) SOUND LEVEL† @ 65 MPH STEADY 18.1 sones (avg) 21.0 sones (avg) CONSUMER INFO BASE PRICE $39,490 $26,485 PRICE AS TESTED $39,490 $39,880 STABILITY/TRACTION CONTROL Yes/Yes Yes/Yes AIRBAGS 8: Dual front, front side, f/r curtain, front knee 7: Dual front, front side, f/r curtain, driver knee BASIC WARRANTY 4 yrs/50,000 miles 3 yrs/36,000 miles POWERTRAIN WARRANTY 6 yrs/70,000 miles 5 yrs/60,000 miles ROADSIDE ASSISTANCE 6 yrs/70,000 miles 5 yrs/60,000 miles FUEL CAPACITY 16.0 gal 15.5 REAL MPG, CITY/HWY/COMB 00.0/00.0/0.00 mpg 18.8/27.2/21.8 mpg EPA CITY/HWY/COMB ECON 22/31/25 mpg 21/32/25 mpg†† ENERGY CONS, CITY/HWY 153/109 kW-hrs/100 miles 160/105 kW-hrs/100 miles CO2 EMISSIONS, COMB 0.77 lb/mile 0.78 lb/mile RECOMMENDED FUEL Unleaded premium Unleaded premium † sones (est) from dBA; the sone is a linear measure of loudness that more closely corresponds to human experience ††Horsepower and torque values derived from 93-octane fuel; EPA fuel economy from 87-octane fuel