I've got a white 1997 Saleen S281 convertible supercharged at 516 HP! 0-60 in about 3.9 sec. It will smoke a Viper. Sounds awesome! And it's for sale (shameless plug). Pics, specs and sound clips at
http://www.saleens281.com/
I also just got a black 2003 SVT Cobra convertible. Advertises at 390 HP, but is really between 425-450 (talking at the crank). Very sweet, but the Saleen makes it look like a kitten. Still, I raced a new Z06 with it and neither one of us could gain an inch of ground all the way up to 140 mph.