I just put in a Uni filter and installed the FMF Q series pipr on my 2001 XR 650 L. I did not rejet because when I went to test ride it responded great. I have great throttle responce and good tork. At high rpm's it reacts great. I live in Texas on the coast and I have read alot of talk about rejetting after a new pipe and air filter. What if anything will I get by rejetting. FMF told me today that I might want to go to a 60 main jet and a 52 pilot. they said they were the same altitude as me. I am wondering if it will make a difference?