I checked this out and the results will no doubt be impressive. However, it seems like a crap ton of fabrication and wiring work.
It would be a comparative breeze to mount a grapefruit sized turbo to the existing 3.2 m104, add whatever aftermarket injection, whatever trans you feel like using, and add LSD. If I wanted a fast w124 it would be a toss up between doing that or a high power 606 superturbodiesel.