a turbo is a supercharger and the point is to get the exhaust out fo the engine as fast as you can to make room for a fresh fuel air mixture. the best way to do that is to open the exhaust as much as you can WITHIN REASON (again). you dont need a 5" exhaust probably jsut a 3"on a 2.4.
and who cares what your car sounds like. jsut make it as fast as you can.