Well i really don't envy you guys in the US with all those restrictions to your dirt bikes. The laws here in OZ are a little more relaxed and after all the free mods are done to my 05WR450F it runs sweet as ! My question is: what exhaust seems to give the greatest boost to the bottom/mid power curve. My last three bikes have been Huskys and whilst i really like the Yamaha i would prefer a bit more of a hit in that area. I'd like to get away with just a muffler if that's possible over a full system. I'd also guess that i'd have to go one clip richer on the needle as well ?