If it was me, i'd shave the head(unless you got the coin to get a aftermarket head, if so hit up noss machine), get more air to that motor with a K&N and outerwear. If you don't ride in the mud, get rid of that airbox and get some pod filters. Advance your timing with a TIMING plate. don't get those degree keys, notorius for shearing off. Get an adjustable timing plate, stick it on +4. Then get some pipes and get all that air you got coming in, out. I think toomey's would be good with these mods. You can pick them up on ebay pretty often for 2-300 bucks.