Chevy Sleeper

Give a year or two and watch a supercharged version will be available.
Also, you've never heard of a Pontiac G8 GXP? It's basically the same car with a different shell. Hell even one of the top execs said "the G8 design was just to good to waste" when pontiac closed its doors.
That said, this car was fielded to the police first and known as the Chevorlet Police Pursuit Vehicle (or PPV for short). I've seen two of them around my area one with the 6.0 motor and the other with the 6.2 (actually got to see the 6.2 up close and under the hood, the cop loved the car and had no problem showing me it and telling me how well it handled compared to the old crown Vic and dodge charger he drove for 2 years).