The hiss is no good. Honestly, I think the 18" CBE sounds perfect. The best way I can describe it is as 2003 Cobra with HFC X-pipe and Magnaflow CBE meets Ferrari F355. Nice and deep rumble at low RPMs which transitions into that mid-range howl the Ford 4.6L's all have and then the higher pitched scream from the F355 at the top of the range.