You're certainly working through the car's maladies very quickly, Mike! The fitment of an expansion tank is something that I'll certainly do to my P6 at some point this year. In terms of panel fit, a P6 with neatly aligned panels always looks fantastic! I've never plucked up the courage to do anything to mine in this regard. I do need to adjust the bootlid, as the gap is pretty large on one side, and ideally, I'd like to adjust the bonnet slightly, as it rubs against the tops of the front doors, which is irritating!
I look forward to seeing the completion of your alloy wheels.