Mrs R, just try it nothing will happen, if you do it your self you'll save heaps of cash, I've owned 4 Nissan gu,s in my time and every one wobbled removing the shims worked every time, no caster corrections, wheel alignments this that just shims and no troubles at all ever. Also what trouble have you heard of? only one I know of is a slightly tighter steering but only slight. You may also get a little veering left and right whilst driving to fix that just screw in the adjusting screw at the top of the steering arm just a little like 2-3mm in max no more. Oh also if you do decide to do it take the wheel off to reduce the weight a bit and I think from memory, there is no other way to get rid of the wobble.