Why are you guys not putting a claim in with local Councils. If BMW say it's having a hard knock on the roads then it's surely the highways fault.
My dad had a punctured tyre and cracked wheel a couple of weeks ago (335d M Sport 18's) and has a claim in with the council at the mo. I will let you know how he gets on but that would be my route.
Golf Ed35 Black with - Black Leather