Join Date: Jan 2011
Location: Clarksville, TN
D&Ds (my choice) are deep, louder than S1 and have great looks.
RPMs are def louder than D&D, but have a raspy sound.
CF are a bit quieter than RPW, but aren't raspy.
S1 is a mild change in loudness.
I've read similar perf #s for D&D and RPW, but haven't seen from others. If a pipe claims it has no need for even an S1 download, I'd expect it's perf gains to be minimal.
2011 CrossRoads (D&D, PCV w/AT, Lloydz filter/cams)
2012 Can-Am Spyder
Twin Turbo Porsche 911
FFR 1965 Cobra 427
2011 BMW 135i convertible
1941 Chevy hotrod truck