I had the same problems with the regulators. Three of them went out within the last four months. The dealer wanted 301.83 to replace just one. I bought the service manual for about $99 from bavauto.com. I bought the window regulators both from the dealer and from bavauto.com from $80-90 each. I did the work myself and now consider myself an expert in window regulator replacement. Bottom line, I saved myself about $500.00 doing it myself. I also avoided having to drive a total of 6 hours in round-trip drives in Louisville's horrible traffic plus the time spent waiting.
I also had a problem with water leaking in from the radio antenna mount. The dealer wanted $459.59 claiming "they had to remove the headliner". I bought the antenna base for $76.00 (still a rip-off because I just needed the rubber grommet at the base. Bastards sell it as a whole assembly) and saved about $300.00 DIY. It was a simple screw-on procedure. 10 minutes of my time.
Total money saved so far on DIY: $800.00.