I recently purchased a car from carmax. I was very impressed. They are a well oiled machine with a well designed sales process. I liked that you can have a car shipped to the nearest location without obligation to purchase (free shipping within certain radius, you are obligated to pay for shipping outside that). In my case I had the car sent from VA to CA. I made the VA rep walk the car and point out any defects. I then had him email me stating it was free of scratches, dents, etc. That way I had a strong chance to get the shipping costs refunded in the event it showed up with damage.
'13 SSII M3 Coupe - KW Clubsport 3-way, Akrapovic Evolution, ESS Tune, StopTech Trophy, IND Euro Front Bumper and Gloss Black Mirror Covers, TMS Studs/Lugs, BMW Performance Carbon Fiber Spoiler/Interior Trim/Center Console, BMW Edition Grills/Gills, BMWPedals Extended DCT Paddles, Mode Carbon GT4 Splitter, Advan TC3, BBS E05