Dont go for powerflow or any of that european shit. Even custom wont get you as nice an exhaust. Go for Jap stuff. For example HKS super drager, or silent power. Blitz Nur Spec, 5Zigen pro racer etc. Yes they cost alot more but there awesome zorsts. You only get what you pay for.... Corsas run around with powerflow and stuff, they dont have HKS or Blitz though (,")