Forks should be using 7.5wt oil, if they have never been revalved, then the lack of rebound dampening from stock would be amplified by the light weight oil resulting in interesting rebound, mostly pushing(understeer)
Theres lots of info on tuning the 07 zoke here
http://www.gasgasrider.org/forum/sho...?t=7087&page=2
Im using bchatt's third setting, and my bike turns inside of everything all day long, although I havent lowered the rear end, I have raised lowered the forks for stability.
This might help