I did the Dave's mod to my 2009 XR650L and I'm really happy with the results. I think it gave about a 60% overall to how it should run. My question is, is it worth the money to upgrade to another carb?? If it's only going to be about 10 to 20% difference then I will probably stick where I'm at. I have done a list of mods to the bike including the FMF,Dave's mod uni filter, gearing, smog removal, redone seat, lowering link, 4.7 and other stuff. What I am more interested in the carb work. It will never be a Power Bomb to me because my other bike is a ZX-14 modified to 182 horsepower and that thing flies. If you have any good input please let me know. This bike is a blast to ride and have no plans of selling it because I have it dialled in for me.