I have had the same experience documented here. I just wanted to let folks know that I was able to locate a kit (p/n 51217263086) containing both left (p/n 51217202143) and right (p/n 51217202146) front door actuators at
www.OEMBimmerparts.com for $94.50 with free shipping.
That is about 1/2 the price of the actuators purchased separately.
I found the same kit part number at
www.KOperformance.com for less $ , but read some posts about bad experience with this vendor. My suggestion is to avoid them and go with OEMBimmerparts which had many good reviews
Update: I received the parts from OEMBimmerparts. They are legit - this is the place to go for these parts.