I gotta ask, why dont you run a more honda 250r style front end geometry? More caster is what i am referring to. In my opinion the honda type front ends float a bit better and are easier to flick into a corner, no bump steer, carries a lot lighter I am saying "stock vs stock".  I have rode the new yfz-s  (pre-09) and they feel heavy in the front, my ltr450 has a bit more caster and has a better ride, the trx 250r seems best out of them all for turning, sliding etc. I am referring to a stock setup, I know aftermarket arms, and shocks, and stabilizers drastically changes everything on all the machines i just mentioned. But In my opinion having some caster to start with makes all the other performance parts work even better.