I would have to agree. My xr was extremely saggy, binned my old tired koni's and springs and replaced all bushes and fitted avo coilovers, welded a bar between the rear turrets and reinforced the inner wings. Raised the ride and fitted a polybushed diff mount (as the standard one sags really bad). all helped extremly well on strightening my rear wheels up running 17's with 215's not and the handingly has substantially improved as wheel as the camber.

shimming the rear hubs substamtially weakens the attachment of the hubs due to the loss of contact area and big strains are put on the bolts instead. maybe ok for a road car as a cheap fix and save a few sets of tyres but personally ride height make a big difference and i'd correct this.