The exhaust systems are interchangeable from 99 to current models. But the exhaust on pre-05 models is more restrictive than 05 and later models. They retuned the engine and made the exhaust more free flowing starting in 05. I'm not sure what the impact to perfornace would be putting a pre-05 system on an 05 or later bike.ltride said:I have to replace the exhaust on a 05 LT. I need to know if I can use an 04 or older. My question is are the header pipes the same size, the rest, if different I can make it work? Thanks for any help.