Resonated vs.
They give you a more refined sound than the loud, aggressive note of non-resonated test pipes. ... The sound on non-resonated pipes can get pretty nasty, especially above 3,000 RPM. If you're just looking for increased power, but don't want your car to be too loud, resonated pipes are the way to go.
Are resonated test pipes quieter?
A resonated test pipe will only be minimally quieter than a standard pipe.
Are ISR resonated test pipes good?
Bang for buck, the resonated test pipes from ISR Performance are very hard to beat. They sound a little cleaner than the pure straight through units but are still very lightweight and non-restrictive. The finish quality is really nice as well.
