If you haven't modified the suspension, you should be good to go. If th suspension was modified prior to you purchasing the car, they should never CPO it based on CPO rules. In my opinion they gave you some BS to see if you can pay them the full amount. BMW does not pay the dealer full listed price for warranty work. The tech does not make much money from warranty repairs either and there is a chance you may say "go for it" and pay for the full price repair yourself. I see these type of posts more and more in the boards recently which tell me that either BMW is tightening their belts with warranty work reimbursements or the dealers get more greedy.
Did you buy this car from them? Threaten legal action if not fixed under the warranty.