I've recently finished documenting an install putting one of Hellion's twin turbo kits on a 2009 Shelby Cobra Mustang that is already supercharged. I thought it had pretty interesting results. The turbos combined with the supercharger pushed 17 pounds of boost into the combustion chambers without overtaxing either system. Final power wound up being 741 horsepower and 743 lb/ft of torque at the rear wheels and the only thing cut up on the car was the cats.
If anyone is interested, you can see the complete install here:
Adding Twin Turbo Power to a Supercharged Shelby Cobra Mustang | Street Muscle Action
Thanks, and I'd love to hear your comments!