C6 Z06 or even the coupe

Heads, cam, and long tube headers would likely do the trick.
^^

Exactly, plus a dyno tune, built rearend, and a few other goodies to make a 300 shot possible and good bye GTR. Sure dollar amount, but it doesn't cost much to make a Chevy fast. They take bolt on to a different level. C6 all the way for money, performance, and looks.

However the rear end is perfect on the GTR -- minus the wing.