I rebuilt mine last year, went from non-ported with pipes, sent crank off and had rebuilt, cylinders ported and stock shaved head, VF3's, I wanted something for trails and wanted it reliable. Ended up at 150 comp, already had FMF fatties and Toomey silencers (how it was when i bought it). I put pods on it and installed timing plate at +4, stock carbs, i feel it is a very "useable" power now. Lots of guys bash FMF's, but ill say this, not much bad is said about Pro Circuits with a set up simiar to mine, but i actually just tested a set the other day and just today i put my old set up back on if that tells you anything. My point is don't be scared of gettin your stock head milled and there is nothin wrong with FMF. (With the right silencers, personally hate the sound of FMF silencers)