your nuts. caddy sts-v with the vette engine and a supercharger. if those are the only two choices i'm disapointed with the new vipers. they are not that fast. the zo6 vette is running 3.9-4.1 0-60. there is supposed to be a special addition zo6 called the blue z06 that will have even more power. the gt carerra is amazing. my boy has one of 5 black ones in the u.s. 60 in 2.4 secs. it does 60 in first gear and the 1/4 mile in 2nd. amazing machine, the only car ive ever driven that the second you let the clutch off you are literally going 50mph. the clutch is so hard it pushes your foot off. still any porsche is gonna blow away your vette or viper just on ride handling and all around luxury. i'd much prefer an STS-V or a audi RS4.