my magnaflow is dual 4"....i always thought bigger was better. the 3" get the same deep throaty sound? one thing for sure....i dont miss that nuetered factory exhaust. aside frm that stupid seat belt magnet thing the only thing i didnt like about the car was the "quiet" . cant seem to do anything for the magnet seat belt holder. anyone out there cure that prob? im 6'2" and it rest rite on my neck in the most annoying way. i feel sorry for shorter people!