I don't see any problem in using 3" couplers if you have 3" piping. There would be no point in using 3" couplers on smaller piping because it wouldn't fit.

My setup is 3" and there was no problems with it.


IonNinja 2005 Saturn ION-2 Sedan 1996 Ford Contour GL - Collecting dust...Zetec project anyone?