hi!
i have NO clue what size the resonator is! But when in doubt, call the 800 # from the apexi web site
BuG the tech guys hehe.
As far as sound, it really depends on how your driving! I can easily pull off stealth mode if there is a cop close bye... but if i have my foot on the gas it's quite loud! It has a deep powerful tone, very clean. It's not too loud when im cruising on the fwy, but it is louder than say the greddy evo or power extreme. Hope that helped a lil... its really something you gotta hear for yourself
