What's it like?
Let's get the predictable out of the way. Many aspects of the interior still can't compete with European rivals. It's quiet, comfortable and well equipped, as is usually the way, but thin-feeling materials, dated-looking instruments and finicky touch-sensitive controls let it down. The boot might be big but the rear seats are cramped, and side and rearwards visibility is not too hot, either.
This all fades into relative insignificance, however, the moment you give the Cadillac's throttle a prod. Blimey, it sounds remarkably like a more refined Nissan GT-R. It warbles along at part throttle, engine note falling to a deep burble as the revolutions drop. Pin the throttle to the floor and a sonorous howl fills the cabin as the ATS-V surges forwards, engine rushing without hesitation towards its 6500rpm limiter.
Putting the power down is easy, thanks to the limited-slip differential, finely engineered suspension and an easily modulated throttle. Unfortunately, the eight-speed automatic transmission proves to be the weak link in the chain. It's usually fine when left to its own devices, but it responds too slowly when you manually command shifts, occasionally leaving the engine against its limiter.
Another chink in the Cadillac's armour can be found when you try to stop the damned thing. It may have staggered six-piston calipers and substantial discs up front, but there's very little feel to the hard, short-travel brake pedal. It's difficult to correctly meter out braking effort as a result, which can initially result in some closer-than-expected calls.
Once again, however, the ATS-V claws back your admiration by cornering in a fashion that you'd never expect. A lightning-quick variable and electrically assisted ZF rack transmits your input precisely to the front tyres and serves up adequate feedback and gratifying heft.
Grip levels are high and body roll almost nil, allowing you to blow through corners at a vast rate of knots; alternatively, disengage the traction control and revel in endless and easily controlled power oversteer. Standard-fit MagneRide electronically adjustable suspension offers a firm but fine ride, bolstering the Cadillac's appeal.
Should I buy one?
Those seeking road-based fun rather than outright track performance will find much to like here. The charismatic ATS-V feels less treacherous than the highly strung BMW M4 when pushed hard and offers more engagement and theatre at lower speeds. Couple these traits with the Cadillac's head-turning looks and rarity and you may well judge its pros to outweigh the cons.
Ultimately, though, the four-star M4 is the superior driver's car, thanks primarily to its better transmission options. Let's also not forget its far more upmarket interior. You could easily overlook the Cadillac's foibles if there was a substantial saving to be had, but there isn't at the moment. Either way, if you made space for an ATS-V on your drive, I'd both envy and applaud you.
It's also worth noting that you won't have to go to the trouble of importing one yourself. There's a solitary UK dealership and, in early 2016, you'll be able to order an ATS-V for around £60k. A three-year, 60,000-mile warranty will be standard and there will be numerous GM-associated service centres to keep them on the road.
You'll have to wait several years for a right-hand-drive version, however, as that's not mooted to arrive until the launch of the second generation of ATS. Here's hoping a manual gearbox makes it over at the same time, too.