A black 2008 300 hp CTS was at Road America (Elkhart Lake, WS) for the Vintage Car races last weekend. It had Michigan plates (not mfg plates) and the owner was wearing a GM tee shirt. I followed him on a "track tour" with my BMW Z4. Track tours supposedly are limited to 70 mph, but that limit is quickly ignored. I stuck on his tail the entire 34 miles of the event. He drove it well and had no trouble keeping up with traffic of Porsches, Corvettes, etc. He had good punch coming out of corners. In corners he was sticking quite well, though leaning a lot.

So, that requires an anti-roll kit with progressive springs?

From my viewpoint behind the '08 CTS it seemed to handle every corner quite well with the suspension it was carrying. Of course, we don't really know what suspension it had, but the ride height seemed to be normal. Typically, an aftermarket or race suspension lowers the car.

I wouldn't expect it to be lowered already. Probably had the FE3 setup anyway...