I agree with Vehix. I've got the catback with the "wheezinator" tip. The first two weeks were awful - with the strange "whooshing" sound at speed (the wheeze). This stopped after a couple of weeks. The next week or two the catback was obnoxious tending towards the "ricer" fake exhaust sound at WOT. This has mellowed to a growl described by Vehix above. I really like the sound now, it's mostly noticeable in the parking garage and at initial startup. During regular driving it's louder than stock, but not obnoxious. The tone is deeper than the rice rockets we have around here, which have a tinn-y echoing sound due to the large exhaust tip. Skullcap has the stock tip with the catback2, and I thought it was too loud - sounded like someone with a hole in his exhaust or manifold. But he likes it so to each his own.

-- John