I'm about 5 minutes away from this dealer. And I have a 2011 X5 - and yes road salt and corrosion are common issues in the Northeast, but if they're taken care of, then you're good to go.
I know West German BMW in Fort Washington, PA - they're not exactly the best dealer - but don't know anything about their workmanship or anything. I have walked into that dealer like 4 times and NO one comes to me to ask if I need help or anything. I've bought cars (5 of them so far!) from Thompson BMW in Doylestown (about 15 miles away from West German) and their service department has always been top notch and very accommodating.
Just my own 2 cents worth. Good luck with the car