Well if it wasn't a Chevy, (especally a Corvette) I would agree that you can't get better then an american muscle car (Mustang with a few upgrades )
But seeing as though i only have the 2 choices, how can you pick the corvette over the car that has been perfected and refined over 35 yrs. The 911 (if thats the porsche your reffering to) has had the same basic design sice the 60's, and been improved upon each yr since. Just because its German doesn't mean its not a bad ass. 450hp in a porsche will knock the socks off of even a supercharged Vette. A twin turbo 911 can do anything better then a corvette, i.e. 1/4 mile, braking, lateral G's (Hell i would be willing to bet it rock climbs better then a Vette LOL) Of course its 114 grand as well.
Corvette, cos theres too many ways to pronounce the word "porsche" when I first moved to america I remember telling someone my uncle has a "porsche" and they didnt have a clue what I was talking about. Till my boyfriend said "he has a Porsche-Aaaaah" or however ye all say it.