re: "...How obliged were they to servicing your gray-market vehicle?..."

I'm not sure what you mean by "how obliged were they", as you obviously know that they have no obligation whatsoever to work on any gray market vehicle -- I've heard that some dealerships won't even let you bring such a car to them -- and warranties are non-existant for grays in this country, anyway. And in any case, my "gray" is 16+ yrs old and has over 100,000 miles, so warranty obligation is a non-issue.

I guess they are willing to work on it simply because they like to work on unusual MBs (and of course, I'm paying
:-). Maybe because it's an unusual model (a given, considering it's a gray) and they're curious, and maybe (possibly the biggest reason?) also because (this gray aside) I'm a regular customer anyway -- I have three other MB's (USA legal) that they regularly service. But in any case, they never balked at workiing on it, except warning that they may have trouble getting a part, or getting specs for an adjustment.

In any case, they are really good techs!