"shortening the wheelbase will only make the situation worse, as its ment for tight twisty tracks when you need more steering by transfering weight to the front. I have too much steering i think."
No, lengthening the car will make it steer a lot. By shortening the car, you make more weight "overhang" on the rear end, adding traction. Shortening may make the car be able to transition more quickly, but you won't get looseness.
Raising the link will add traction. Better yet, put a .75 or 1mm spacer at the hub, raising your ballstud. That will add traction.