I have had mine on now for about 4 months and the overall experience has been good. No cell. The sound in definetly louder than stock. My only complaint is that I feel as if sometimes it is slow to take off when a good hard push on the pedal is required to get out into traffice. Anybody else experience anything like this? I'm cosidering spending the $6-8 and putting on the ground from the negative terminal to see if this can get rid of this issue. I have a 2008 hatch MZ3 5sp. Thanks.