I use the Nashville dealer and they're always good. Plenty of M's here, not like ATL though. They can also get you a loaner if you ask nicely while booking the appt.
Current: SBM X5d, Jet Black E46 M3, Black FJ Cruiser, 1970 240Z
Former: '11 MCB E90 M3, 2011 Lotus Exige, 2003 350Z, 2002 WRX, 1996 Supra turbo, 1984 320i, 1987 E28 M5