I met the owner of a supercharged 2010 V6 Mustang at a track day. He claimed to have about 350 HP to the wheels and the car moved pretty well for a V6. He did have quite a few modifications though. Intake, supercharger, headers, high flow cats, exhaust, custom tune, etc... He also had some suspension and brake upgrades. By the time he was done, he probably could have bought a G, but he was paying much less in insurance than he would on a GT.
Sounds about right. My sixxer was pretty cool. Even a lot of the V8 guys I hung with gave it respect. It was able to hang with or beat most 3 valves that were midly modded (intake, tune, exhaust). The torque curve from the Eaton MP90 was just awesome. The best part was that the only mod you could see was the dual exhaust conversion...otherwise it was a total sleeper. When I floored it all that you can hear was the blower whine! weeeeeh!