I recently purchased a used 2010 M3 here. I found the car for sale through BMWUSA.com and gave these guys a call. I spoke with Michael Turpin and worked out a price both sides were happy with and put down a deposit so they would hold the car for me until I could check out the car in person and finalize the deal (I live in LA).
The car was as advertised and Michael even offered to pick me up at the airport and drive me to Chase to finalize my loan. I ended up not needing either but it's the thought that counts!
Overall it was a friendly and painless transaction.