Nearly two years later I have information answering my original question. I have used two different BMW independents in the Triad. My preference is Absolute Automotive in Asheboro. The owner has considerable experience with German performance cars. Absolute did my suspension re-work last year and has dealt with a recent CAN bus issue caused by an upholstery shop not disconnecting the battery prior to removing the driver's seat. Lots of folks in the area have Absolute check out their cars prior to going to VIR, so its not uncommon to see a Corvette, M3, Miata or other performance car in at least one of the service bays. Good prices and straight talk.
http://www.absoluteautomotiveandperformancellc.com/