HI.. all CRZ owner.. last week a exhaust specialist told me that CRZ should not modified the original exhaust..becoz will downgrade the torque and top speed of the car..he told me use back the original better..but another foreman tild me that if the exhaust system is already made like spoon or hks can use..if customize whole exhaust system from outside cannot use...so nid some advice from other who specialist in exhaust system..