Sports coupes reside in that Rhode Island-sized space between fully indulgent sports cars and eminently sensible sports sedans. To earn its garage slot, a coupe must adroitly juggle three somewhat contradictory attributes: sex appeal, driving joy, and 2+2 practicality.

The three premium coupes in contention here pit youthful cunning against confident maturity. The Cadillac ATS and Lexus RC350 F Sport are the class's pop celebs; think Justins, as in Timberlake and Bieber. Hollywood legend Clint Eastwood-with 60 years of acting, directing, and scoring to his credit-is the Audi S5 analogue. Roots reaching back to 2007 didn't inhibit Audi's veteran sports coupe from busting BMW's then-new 435i in our 2014 comparison test, so we took it and threw it against these fresh newcomers.

Achieving spec parity for this $50,000-plus trio was a challenge. While the Cadillac and the Lexus both offer four-wheel drive, a core Audi standard feature, ordering that option adds weight and cost we chose to avoid. Also, the S5 is the perform¬ance A5, whereas the four-wheel-drive ATS and RC350 coupes are intended more as all-weather interceptors than dry-road speeders, as indicated by the following facts: Cadillac locks you out of the ATS's most aggressive suspension and Lexus doesn't include rear steering if you choose four driven wheels.

A V-6 is standard in the Audi and Lexus, so selecting Cadillac's 3.6-liter six made more sense than going with its power-lean, torque-rich 2.0-liter turbo four. That choice aligns the three power peaks, though Audi's supercharged-small-displacement strategy gives the S5 a significant torque advantage-325 pound-feet versus Cadillac's 275 and Lexus's 277. Most of that extra grunt is nixed by the S5's prodigious curb weight (3954 pounds), or 70 pounds more than the RC350 and 394 pounds heavier than this ATS coupe.

To winnow the great from the merely good, we ran these two-doors through our test gantlet in California City, California, then mounted a southwesterly trek crossing the San Andreas Fault to Jalama Beach on the Pacific Ocean. Thanks to tectonics run amok, fastidiously maintained national-forest roads, perfect weather, and minimal traffic, we enjoyed hundreds of miles that are worth replicating in heaven. All right, who's feeling lucky?

COMPARISON TESTS
Digging deep to create what it considers a "radical coupe" (which is the model name decoded), Lexus combined its hottest V-6, portions of the ISand GS unibodies, and some ambitious chassis hardware, along with lessons learned from its LFA supercar. Designers contributed a spindle grille mean enough to wind steel cable, aggressively sculpted side surfaces, Vegas-grade lighting, and many air vents, some of which actually function. Inside, there's a lavish array of stitching and trim in several hues and surface finishes. Combining the underlying Lexus spirit-a supremely smooth, quiet ride-with optional F Sport equipment brings enhanced performance to drivers of widely varying skill levels.

Our $43,715 RC350 base test car was embellished with a $3985 F Sport package (faux-leather sport seats, variable dampers, exterior trim, and 19-inch wheels and ¬summer tires), a $2610 navigation and entertainment upgrade, a $1900 variable-ratio-steering and rear-steering combo, and $2195 worth of other options.

Some of Lexus's dreams come true, many do not. In the normal driving mode, the RC350 shows poise any grandma would love. The engine hums with nary a harsh note. The transmission hurries to overdrive, ride motions are plush, the steering is light to the touch. Turn-signal clicks are barely audible.

Twist the mode selector to sport-plus and an alternative personality stirs. The suspension stiffens, the steering quickens, and the engine hustles toward the redline with bared teeth. Unfortunately, perform¬ance parity proves elusive. The test's poorest power-to-weight ratio lands the RC350 in third place for acceleration and passing. Grip deficiencies and mediocre weight distribution stretch stopping distance and hobble cornering speed. Hustled through the slalom cones, this car turns enthusiastically, then stumbles into crippling understeer. Are the rear-steering wheels, the tires, or the engineers to blame? We suspect all are.

Back-road moves are also a mess. The light, quick steering fools you into diving into bends too aggressively for the available grip. Brake-pedal mushiness saps confidence. Ride motions are jiggly and induce abundant head toss.

The interior report is just as grim. In spite of the test's highest roof, front and rear entry is a chore. In back, the view out is restricted, cup holders are AWOL, and there's minimal wriggle room. Front-bucket comfort and lateral support are excellent, but while the Audi and Cadillac provide adjustable thigh cushions, Lexus skipped that feature. Outward visibility is hurt by a high cowl and oversized mirrors.

The touchpad that operates the RC350's infotainment gear is a good idea and a convenient reach, but matching mouse motion to cursor position is tedious. One cool feature is a gorgeous electronic tach that can slide horizontally to reveal secondary gauges. The mystery is why speed is reported only digitally when there's ample black space under the instrument shroud, used only for a few warning lights.

Overall, the Lexus RC350 feels dithered, as if Justin Bieber shuffled onstage after a tour-bus binge.

Encouraging news: Cadillac's by-the-gram weight-saving strategy and focus on core attributes such as structural rigidity, chassis balance, and driving dynamics paid off with a sports coupe that's a worthy alternative to imported rivals.

The exterior design is intentionally less polarizing than the CTS and ELRcoupes. That spots the ATS comfortably between the classic S5 and the flashy RC350. Proving that this brand is serious about shedding more of its fat-and-finned baggage, this is the first production Caddy in half a century without a wreath to fossilize its crest, which has also been modernized.

To invade nearly every sports-coupe nook and cranny from $40,000 to $60,000, the ATS coupe is available with a choice of two engines, stick or automatic six-speed transmissions, rear- or four-wheel drive, and four trim levels. Our $52,315 Premium-package 3.6 test car was enriched with but one option: a $995 "Red Obsession" paint job. Alert the authorities.

The ATS's strategic advantage is this test's lightest weight and best balance. Thanks to a chassis tuned for minimal understeer and a decent set of Bridgestone Potenza RE050A run-flat tires in staggered sizes, the ATS topped the field in cornering grip and maneuverability (slalom) testing. Adding throttle at the adhesion limit glides the tail in manageable increments, a rare quality in today's cars. This ATS also earned braking kudos with a 70-to-zero stopping distance 21 feet shorter than the RC350's and 10 feet better than the S5's.

Acceleration was less endearing. Even though the ATS packs the largest-displacement, highest-revving engine, it bows to the Audi S5's superior combination of torque, traction, and shorter gearing. (A lighter Performance-edition ATS powered by a turbocharged 2.0-liter four-cylinder and equipped with a manual transmission was slightly slower in previous testing.)

Logbook entries worshipped the ATS's road manners. The ride is firm but never verges on the painful, with body motions appropriately snubbed at speed. Steering response and effort are both nicely calibrated to buttress the driver's sense of command. The brake pedal responds to pressure instead of travel, providing clear feedback and easy modulation. Add grip that keeps on sticking and you've got a sports coupe that beats the S5 in entertainment values, if only by a hair.

Unfortunately, the ATS's powertrain doesn't carry its share of the freight. The engine shakes like a frigid canine at idle and howls like a tormented cat when running to the redline. At least the transmission makes amends by holding gears until the driver taps a paddle shifter, the only autobox in this test so fully obedient.

The ATS's back-seat entry is inhibited by front belts that won't get out of the way. The front buckets have barely enough backrest wrap, lower bolster firmness, or upholstery grip to lock an occupant securely in place when the driver takes full advantage of this car's handling prowess.

Cadillac's CUE infotainment-control arrangement drew screams of indignation. The major issue is the touch-sensitive screen, with buttons that are finicky and difficult to manage with a limb wobbling in space. We prefer the more comfortable and user-friendly console-**** approach.

The ATS's strong second-place finish earns it the Justin Timberlake trophy. This Cadillac is clearly steeped in talent, but there's more potential left. We assume that the coming V edition will bump it up a notch.
Yes, it's familiar-looking, expensive, and seemingly past its sell-by date, but none of that stopped the Audi S5 from winning this comparison without breaking a sweat. The key to its success is a compelling repertoire. Every move this sports coupe makes affirms its champion status.

This middle child of Audi's 5 family starts at $53,425. Our test car was blessed with four options: a $2900 Technology package (navigation, infotainment, side warning, and rear parking assist), a $1400 seven-speed dual-clutch automatic trans, an $1100 torque-vectoring rear differential, and $500 carbon interior-trim adornments.

When Audi replaced its stunning 4.2-liter V-8 with a supercharged 3.0-liter V-6 two years ago, there was much gnashing of teeth, but the downsizing turned out to be a shrewd move. In spite of a slight loss of power, the broader torque curve and improved front-rear mass distribution paid huge dividends: more-agile handling, quicker acceleration, and two additional miles per gallon (partially attributable to a seventh gear added to the transmission).

Aside from the powertrain changes, Audi has resisted fiddling with its successful formula, indicative of its grasp of well-rounded performance. The supercharged V-6 and the seven-speed dual-clutch automatic bond here like Thelma and Louise. A nudge of the throttle delivers a subdued growl and an endearing swell of thrust, multiplied by a smooth downshift if you demand more. Seldom exploiting all of its 6800-rpm rev range, the S5 is the swiftest car here by a wide margin. Whipped, its engine sings opera that shames the Cad and Lex.

The S5 lands behind the Cadillac in handling and braking in part because it's heavier. On the skidpad, when front-tire grip begins to wilt, coaxing this Audi back in line is difficult. Its penchant for understeer also impedes this car in the slalom. But on the road, supple damping plus ideally orchestrated steering effort and response do indeed make your day.

Audi seals the deal with an ambassador-grade cabin. Except for one gripe about too-aggressive lumbar support, the firm-but-supportive front seats generated high praise. The rears are more accessible, roomier, and better furnished than those in the ATS and RC350. While all the rear backrests fold and split, this is the only one with a fold-down armrest and a pass-through for skis.

Trim fits and finishes are impeccable, and Audi's MMI **** is our favorite for infotainment control. The S5's instrumentation is traditional but flawless from legibility and aesthetic perspectives. And this is the only sports coupe here providing a handy slot in its console for a smartphone.

For its versatility, engaging personality, and convincing performance, this German Gran Torino may be a fistful of dollars more, but it still earns our Dirty Harry achievement award.

I'm sick of Cadillac not offering a mid-line V8 option(or a decent V6) in their lower line cars. Few people can afford a 650hp, $85,000 land missle CTS-V or want the compromises that come with what is basically a Corvette with a sedan body. I'm glad Cadillac has the ***** to make the CTS-V, but something more affordable and smoothing riding with a V8 would be nice too.