I've been very happy with my fmf gold series fatty, as well as just about everyone that runs one ( especially over stock ). I think a point that needs to be stressed reguarding exhausts is the difference between silencers and headers/downpipes. Silencers are mainly for sound, and slightly improve performance. A header/downpipe is where the noticable gains in performance are. Some good cheap mods would be head work as said above, flywheel lightening ( higher revs ), advancing your timing which is free if you DIY, after market reeds greatly improve throttle response over stock, and either remove your airbox lid or what I personally recommend is buy air box vents for $10 and remove your snorkel.