My previous car was a 2003 SVT cobra. It had various modifications but the primary power adder was the 2.8L Kenne Bell Twin Screw supercharger. The car made 642rwhp//605rwtq @ 22 psi on 93 octane. Yeah the car was scary fast and could out run an production car out there --- but it was loud as hell, extremely poor gas milage, and felt very uncivilized compared to my M3.
Sometimes, I admit, I do miss the raw power of the cobra. But IMHO the M3 is a much better all around balanced and fun sports car.
And if your just looking to get a speed fix go out and buy a crotch rocket. the 850hp vette cant touch that trust me.