notice that the exhaust pipe aft the resonator is not concentric?

I just saw it last night when installing my addco rsb... I was thinking WTF!!.... why couldn't they had put a contric fitting instead of the semicircular (squashed looking) fitting...

 

yeah, that's part of why stock exhaust is restrictive

 

who designed it oughta be smacked in the back of the head.... I think he added several steps to the fabrication by doing it that way...

 

Should be a good enough reason to replace it...with a Greddy.