I would try to persuade the dealer to do the Bilsteins all around in place of fixing XREAS - it will likely cost them less in parts and labour than fixing the XREAS system. The main reason I would do it however is its pretty likely they will fix it (ie patch it up rather than replacing it entirely, which is what it sounds like the plan is) and it will work for a while and then you'll spring another leak, at which point you won't be able to really argue it is a pre-purchase issue anymore and will be stuck with the cost of doing Bilsteins anyway. It boils down to how much time you want to spend at the dealer over the coming months![]()