Just installed mine yesterday and I really don't find it as loud as I thought it was going to be. It sounds a little more ricey than I thought, but it is definateley a lower pitch than a ricey one. Overall I think it sounds good, I think it will sound better later. The noise on mine is no louder than my tire noise (under normal driving, if you step on it it will get loud but not too loud). And if it hits that "beer bottle effect" then just let off the gas for a sec and reapply, it seems to go away 90% of the time. Of course I have only drove one day and I don't think the beer bottle effect happened inside my cab, but I could hear the tone of the muffler that you are describing (I just let off a bit and it went away) I had my muffler mounted up front due to Tones post

I love the sound of it when you start it up, it just puts a smile on your face. Track times with this mod coming Monday.