Hey that's only a couple of miles from me (thought that crane in the background looked familar) - our house is almost on the find-us map on the web site. Tempted to pop in to see it in the flesh (or if anyone's interested and wants an opinion).
One practical problem I can see is the access to the inlet manifold return valve.This is mounted on the rear of the cylinder head and needs cleaning periodically or the car will run rough.A common problem with this engine.
Access on my old BMW 740i was somewhat tight but if you look at the W124 engine bay pic it's clear you have even less access to the rear of the engine.
Having said that this V8 may have been an even tighter fit into the E34 540i shown here with the cam cover off.
Respect to the guy for doing that. Must've been very hard work. The E34's achillies heel is the space in the engine bay...must've been worse in the Merc.