I've purchased the extended warranty for every new car I've bought in the last 15 years and I've at least broken even compared with dealer retail prices. If BMW asks $1500 for an extended warranty, they expect it to cost them less than $1500 on average. But I don't think BMW NA could pay a dealer the same shop labor rate that a retail customer is charged, and no matter what the invoice says, they are supplying the parts at a fraction of the retail cost. By buying the BMW warranty I am prepaying for expected repairs, which BMW discounts.
Alternatively, if I have an out-of-warranty car, I'll be sure that I have a tame independent shop to take it to when it breaks.
2008 E91 station wagon 19K miles "Classic" BMW inline six, six-speed manual transmission, Alpine, Terra, Xenons, ZSP, ZCW, ZPP, PDC, CA, alarm, M shifter and M brake handle, Euro rear fog light switch, Euro aspheric mirrors, rear power outlets, Dunlop Winter Sports, Garmin nüvi custom cupholder mount, Lidatek, V-1 built-in remote display, tire pump, jack, floor mats, sand, dog hair, several pairs of smelly old running shoes.