I love my V! I was a bit apprehensive about having a six speed manual, as I live in a large city and spend time in stop and go traffic. No problem. The CTS-V handles, shifts, and runs great. The clutch is easy without being too mushy. My previous toy was a 2001 Mercedes C32 AMG. The Mercedes was fast, but I got tired of the lag that comes with supercharged engines. I also got tired of visiting my local Mercedes dealer regularly for engine repairs. The V has great low end torque, courtesy of its' 400 hp eight cylinder, handles incredibly well, and sings sweet burble music via the exhaust. For a car guy,this is heaven!
Engine, Onstar telephone service, navigation system, seats with suede inserts, tire pressure display, just a well designed car.
More back seat leg room (although it already has more than the STS), a computer / display system that allows more than one piece of information to be displayed at a time (can't display outside temp. and fuel range, or anything else concurrrently), add some additional exterior/interior color schemes.