Just noticed a bit of uneven wear on one of my rear tyres so had a peek under the wheel arch and spotted this

Rear strut.jpg

According to VagCat boards this is called a stop buffer. My question is, is it load bearing and thus possibly causing the tyre wear? I found a kit from Sachs, search. Can anyone recommend Sachs suspension as it's a good excuse to replace the shocks aswell? Would it be worth doing the top mounts too?

TIA