A friend of mine put one on his tour and it sounds like a 4 cylinder but not as high of pitch. I haven't heard it at a real high rpm yet. But it sounds alright just driving around, even though I wouldn't do it to my tour.

1999 Black SE Sport No engine mods...yet Alpine 9833, (2)Kicker 12" CVR, Fosgate Power 800a2, Infinity Reference 5x7's, Stinger wiring