I recommend the warranty..
I have over $12,000 in repairs (including RFT replacements) on an extended warranty I purchased in 2009 for $2250.
The $12k doesn't include 30 or more days of free loaner cars provided while the car was being fixed.
If you are a mechanic, have a friend whom is a BMW mechanic, have your own lift, then I would take the risk. Otherwise the old adage still holds true. "You don't drive a BMW out of warranty.
I bought my warranty from easy care warranty.