Here is a video comparison from just spiral flows to both spiral flows and magnaflows. The video doesn't really do it justice. I went this route to tone it down a little. It is much cleaner at higher rpms. Cam specs in my sig
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Ride: 2001 Z28 M6
MODS: Z06 Rims, LCAs and Relocation Brackets, Eibach Lowering front springs, TSP 233/239 .595/.605 113LSA, PaceSetter LT's, TSP True Duals, Spiral Flows + Magnaflows
Videos: http://video.ls1tech.com/uploaded/776073.htm