Dan, for starters I have the Winter Sport M2's on my Z3. and I love them. Last week we got 18 inches of snow, and I was plowing into my subdivision with the airdam of the car. They are Awesome! As for the re-mounting, that is riduculous. I would say I may see one out of every 200-300 packages needing rebalancing, but it is very rare. In any case, if you did need that, i'd pick uo the bill anyhow if it went out of balance in transit to you. No need to worry. If you get a free moment, give me a call and we can put a quote together for you. thanks Aaron 800.428.8355 x395