I have a supertrapp Pro on there now. I hear that they are louder than most, but it is not that bad. Reason I am getting rid of it is becuase the mounting eyes to the frame are all cracking in half. Pretty soon it will just be hanging by the head pipe. I was looking at the FMF Powercore IV units. Seem pretty nice. Also the yoshimura and big gun systems. I already have an aftermarket pipe on there (dont know which one, came on the bike) so I dont need a complete system. Thanks!