I purchased a used Subaru for my son's first car from BMW of Denver that I found while performing internet searches for this specific model. My sales rep was Nick Nichols. I had a very positive experience.
The car we purchased was very clean, in great shape with no concerns. The car went through a through inspection and replaced fluids, tires, brakes, etc before they listed the car.
Because both Sonic Automotive and the specific BMW dealership have a reputation to uphold, I feel confident that they would not sell a bummer of a used car and their inspection caught any concerns typical with purchasing a used car. So far that theory also has been panning out in the week we have owned the car and have been looking at the car in greater depth at home. The price was right as well compared to the other dealers.
Nick Nichols, the rep I worked with, was very informative, very professional and nice to work with. I would recommend working with him. He is very knowledgeable on the car I purchased and I am sure the expertise translates to BMW's. He seems like a car guy who knows his stuff about the finer details of cars.