Update: It was an EXCELLENT experience, and I am surely going to be using the Mercedes Garage for my servicing and installation needs.
Johnson IC pump installed, wiring adaptor replaced, old adaptor returned with old pump "in case of a need to switch back to stock", all for $205 total. The size of the OEM pump is almost twice that of the CM30...
While waiting and observing the job, saw quite a few other MB cars coming in and out. There was a real nice gold 1970 280SL roadster with a broken top, but they fixed him up quickly after finding and replacing a missing bolt in the folding frame. Saw a few SL500s as well, but my XF SRT engine looked the best

If you need reliable help with your XF, this seems like a good place to start.