CTS-V is one hell of a bargain for what you get....it was tested at the nurburgring, as well as GM's "baby ring" here in the states(maybe they got a little overzealous on the suspension tune from such testing). Its really an amazing piece of work, and easy on the peepers....BUT.....
Im a M guy through and through,and we all know why.
I would do just about anything to get my hands on a M5...any one of em.