try slightly lifting the throttle just before u turn, as soon as u have started to turn, gently get back on the throttle and try to find a balancing point where it drifts around nicely without losing too much speed, too much throttle and it will snap back to understeer. its a very fine line, and u cant get back on the throttle too early with 4wd, or u are back to understeer again. much the same as driving a 1:1, its down to the weight transfer of the supension for setting up into a corner.

i had the same issue with my rally setup, i made up a rear anti roll bar to help stop the front inside wheel lifting when i got back on the power, it helped quite a lot - i think there are some pics in my signature link. i also softened my suspension quite a lot to allow more weight transfer so it was more obvious what was happening and when, and what caused what to happen to the handling etc, whilst i was driving it... it helped me to set it up to my driving style - it ended up a lot softer than i thought it would.

an uprated servo and a tight servo saver will help it all regardless of setup tho

hope that helps