Diff Ratio Dilema

Spoke to somebody years ago with a supercharged 300C SRT8, he changed the factory 3.06 gears out for whatever was available for the Challenger at the time, something around 3.5 I think and he reckoned it was the best bang for buck he had got out of the car. Just remember that the SRT8 300 runs 20" wheels, which will be a bit taller than your regular Valiant wheels.