I rode with a friend this weekend who had a Canadian 426. He didn't need to do any of the free mods, but he did change his exhaust timing to the YZF setting. I think he said he turned the exhaust cam back one tooth? My 02 has all the free mods already and it runs great, My question is, will changing the timing on the exhaust cam make any noticeable difference in performance? If so, how hard is this mod to do???