Porsche of Arlington...10-year relationship (hooked up right after I moved back from Stuttgart-Botnang)...no drama, no problems, good people, excellent work. My car is in top shape and driven...from West Palm Beach to Montreal. Sorry to hear about your problems, brothers.
Some dealer do suck. I have an MB too and I can tell you that Mercedes in Arlington is the worse (long stories). I'd rather drink battery acid than do business with them.
Tony