We use BG products at work, and they are very good! Made here in Wichita, KS too
Unfortunatly, at Bavarian Automotive, we have nothing to do with diesels. I doubt my boss would take in a diesel BMW
But the BG stuff for gassers we use. Our customers love the stuff too. We've used BG's 244K fuel system cleaner in my former old 95 stroke and it helped it out. I use BG's fuel conditioner in my diesels too, tiny bottle and treats alot of diesel. Use that for lube to ULSD. We've ordered some diesel stuff for a few customers too. I have heared of the the diesel cleaning tool too.
Myself however, i would remove most of the fouled intake system parts and clean them by hand real well, till bare clean bare metal again. And then use an intake cleaning system to follow up with the hard parts.