And that's essentially what it is. Only it isn't as the ATS is an entirely new car built off a completely, all-new-from-the-ground-up platform. Car companies, least of all luxury ones, don't get to build new platforms - the basic fabric of a car other than the body - very often as they cost an immense amount of time and cash. So this ATS saloon is not the only car that is going to be built off it. Apart from all the ATS model derivatives, the ATS's skeleton and nervous system will be reworked for the next Camaro, the refreshed CTS and a new Chevrolet compact coupe, which we know only as the 130R concept car so far.
OK, so it's the smallest Cadillac?
Yes, think of the ATS as a BMW 3 Series competitor. As that's exactly what it was conceived and designed to beat. Cadillac has watched as the 3 Series has become the default luxury compact car in the US, and has had to wait until now to bring the fight to it. It's a massive task to try and topple the Bavarian uber saloon, but Cadillac reckons the rear-drive ATS is the car to do it.
The company proved, as much to itself as the rest of the world, that it could build globally competitive luxury performance saloons when it debuted the mighty CTS-V model back in 2004. Now it's taken all of the key learning from that car and applied them to the junior ATS, plus a truckload of new tricks.
OK, but it's not just about performance models, what are the regular cars like to drive?
Good to great. We got to drive everything from the base 2.5-litre manual model all the way up to the 3.6-litre V6 variant and the general impression on the road is that the chassis guys have really done their homework. Super smooth ride, good steering feel and quiet, finely controlled suspension let you know immediately that this car means business. The base engine is a little coarse when extended and the smooth 3.6 bent six will please the more mature driver, but the sweet spot is the two-litre turbo unit, especially when it's mated to the tap-shift auto gearbox. In this configuration the ATS gels into a back road weapon that has you snipping up and down gears and slicing through corners just for fun. Word of caution: do not spec the manual.
Any other standout features?
Yes, the (optional) actively damped two-mode suspension. In a lot of cars with multi-mode suspensions you can only tell the difference if you are a student of pre-stressed and ordinary concrete. In the ATS, you effectively get two cars. The first one is a comfortable cruiser with enough body control to keep things interesting and tidy. The second one is an all-out scratcher that, still without being uncomfortably hard, tightens the car's movements allowing you to be extra precise with the steering and throttle, and being rewarded for doing so.
How do you know that?
We got to drive the ATS on a short race track in Atlanta that felt like it had been designed - by F1 guru Herman Tilke, no less - after a blast across some hilly British countryside. Just fewer sheep on the road. The 50/50 front/rear ATS was completely linear and rock solid throughout, to the point that you start to think you are a better driver than you are. That kind of flattery is always welcome - and rare.
So, better than a 3 Series then?
At the limit, it really does feel that way. On the road, the fight is more even. The ATS's cabin doesn't have the BMW's super modern feel, settling for a more traditional stitched leather approach, which will please some and deter others. But it does have some nice, unique touches. The CUE control centre is big, bold and easy to use with words - it understands ordinary language instead of expecting you to speak like a robot - or fingers. And there is BOSE active noise cancelling, which keeps the cabin free of unwanted noise, just like your headphones on an aeroplane.
Is it a good buy?
With prices starting at a bit over $33k, which is less than the 3 Series, yes, it is definitely worth a look. The model to aim for is the two-litre turbo with the tap shift auto box and the active chassis. The 3 Series now has a new and serious US competitor.
Specs (as tested)
2,457cc, 4cyl, RWD, 260bhp, 353lb-ft, 27mpg, CO2 n/a, 0-60mph 5.7secs, 155mph (est), 1530kg
From $33,990 (£21,883)