Yeah you need either plastic or metal (ideally the metal) shims you can buy the metal of eBay or atomicmods, you get he plastic ones as part of the GPM knuckle kits - I have them in my evo8 and they do the job but being plastic they burn away from friction and the problem comes back - I also have a bunch of metal ones which I really should fit!
Get them from:
http://www.atomicmods.com/ProductInf...roductid=10009
or
eBay if you can find them.
You need 8 in total 2 on each wheel between the bearings and the gear arm.