I have a 2000 modal which is about the same as the 2004 modal. I have put a nice 4 into 1 exhaust system from Mega cycle. I´ve upgraded the front and rear suspension by promecha who have a great understanding of these bikes. I´ve had slight work on the carbs which overall has made the bike much improved. if you want to turn a great bike into something awsum it´s well werth the effort. my only disapointment with this bike are the breaks. I will find a way to overcome that as well.