You'll find the BMW insured warranty is worth it's weight in gold. If you have a problem and take it to the dealer, as long as it's not bodywork, trim, or seals, the dealer will try their damnest to get the work approved by the warranty company.
The dealer gets paid direct from the warranty company, and therefore the more work they can claim for the better.
I had both my turbo's replaced late last year under the warranty (which was just wastegate rattle) there were no issues making the claim, The dealer had the car for a week, they gave me a courtesey car to run around in, and the final bill would of cost me £3-4k.
Paid for itself on the first claim!