Besides what Socalwrench listed. My brother has one of the new ShelbyGT/SC's. Currently it is a 1 of 1, and yes he drives it (not a trailer queen) The GT500's are built at a ford plant the ShelbyGT's were GT/CS mustangs that were shipped to Las Vegas to be modded by Shelby techs. My brother went with the Whipple twin screw SC and it's rated "around" 530 hp. He has not had it dyno tested but I can tell you from experience it will move on down the road.

One of the biggest differences is the weight ratio. The GT500 is nose heavy compared to the rear of the car. The ShelbyGT (without the SC) was like a 51/49 weight ratio. Really built for track racing or going fast on the "twisties".

The newest package (SR) is a Super Snake package for the ShelbyGT. My brother's already salivating to have his car modded to this package, granted he already has a lot of the components but I'm not sure he needs more reasons to drive the car fast.