I'm a newbie, so take my comments with a good size grain of salt.

Since much, if not all, of the mechanical and electrical on the XF are the same as the Mercedes SLK320, for me, logic says to think of those aspects as not being Chrysler.

I suggest you look for a well qualified independent Mercedes shop. By pure chance I've lucked out in that my daughters long-time boyfriend is the head mechanic of one. He said that he'd had several XF's in the shop and apparently there wasn't anything mechanical or electrical on the cars that he couldn't handle. He did mention that the superchargers on the SRT6's have a tendency to go 'out;. I also have a Limited so that's not a problem for either of us.

Also by chance, I bought my 2007 Limited from a used car dealer in Carroliton.