Back Pressure

I know n/a cars require backpressure in order to run well, and turbo cars try to have as least exhaust restriction as possible, but what about Supercharged cars, they run higher compression then turbos but also produce less boost, so do these cars require backpressure, or do turbo exhaust rules apply?

backpreasure is required on all engines.

Turbo cars get their backpreasure from the turbos. Becasue the turbo provides the backpreasure the engine needs you can free up the exhaust after the turbo to a greater extent than non turbo'd cars.

Superchargers have nothing in the exhause flow so they would not have any effect on the kind of exhaust you can use.