Purchased new exhaust from e-bay Got the pipe yesterday, so I unrapped it, it's the model # 2003 for the yz, needed the #2004 comes with the sparky, ---- w2do, :lol: put the itch on, scratch--scratch--, 10 min. tops-- and it was on --- needed to put a spacer(washer),!, between the mid pipe bolt to give the pipe some room to clear the sub frame and loosened the header slightly, no biggie. The fit was perfect!! Pulled the choke- gave it a squirt--hit the button-- :banana: :banana: It is loud, thought to myself?? not gonna start this up at 6am to go to work!! Just came back from a ride---- it has become a whole new animal didn't go too far, farmers field drive through??-- perfect for a drag kinda thing? for a bout 1/3 of a mile, 4th gear - pull on the gas --- she is up --- be careful I thought-- just finished rainin thunder about an hour ago -- about a half hours worth!!! --- flippin purfect traction fun stuff -- but im only in swim short-with gear?? so I lapped it about 4 times up and down. To see how the ais jetting is workin? Runs pretty good, slight bog once in a while???? will need to play a bit -- I'll try the O-ring mod first, set the links and a-p squirt -- if I have too ?? need to get to some tecnical riding area to really see whats up!! AS far as the sound --- it's a sexy itch --- awsome sound --- but it is loud --- ??? will find a s.s power bomb header to tone it down a little, it's just to loud, and when I order some packin, an insert is in order for riding around town! Did I mention the Smile Factor -- wow, the differance is huge compared to the pee shooter with the ais kit!! I would say it gained 5hp easy, or so it seemed.