The ATS' ride quality is confident and comfortable. A difference of 1 inch in wheel diameter isn't always noticeable, but I found the 2.5L with its 17-inch wheels to ride a little softer than the other versions I drove, which had 18-inch wheels. The difference was felt mainly over rippled surfaces and tar patches.

All engines and trims come with the same suspension except for the Premium trim level with rear-wheel drive, which includes Magnetic Ride Control, or MRC. This adaptive suspension automatically adjusts shock-absorber firmness on the fly to match road conditions. It teams with upgraded Brembo brakes and Bridgestone Potenza summer performance tires.

It seems unwise that all-season tires aren't offered with MRC. At minimum, all-season tires should be a no-cost option. Perhaps the thinking is that anyone who's concerned about wintry conditions would buy the all-wheel drive, which rules out both MRC and summer tires. But that raises a question: Why should MRC be denied to anyone who wants all-wheel drive or all-season tires? Cadillac needs a solution here.