Well, here is a Viper (yes, I know a Gen II) vs. a GT3 cup car. The Gen III is an even better platform, yet the Z4 is supposed to be better???
http://videos.streetfire.net/comment/0/c4008615-1482-4ad8-8cf4-cec4e56e83de.htm
http://videos.streetfire.net/comment/0/c4008615-1482-4ad8-8cf4-cec4e56e83de.htm