First, I don't know diddly about old BMW's - never owned one, never wanted to own one, unlikely that I will ever own one, because BMW's don't interest me, and probably never will.
But I've owned old Jaguars of that era, including a twelve cylinder, which I still own.
Second, the electronics on cars is simple stuff. It's just feedback loops. Feedback loops are simpleton easy, and as long as you are willing to learn the systems and operating parameters of the loops, they are easy to diagnose and repair.
Third, it's my experience on the old Jaguars that the electronics almost never go bad. It's literally the last thing I look for. What gets glitchy is the connectors on the wiring harnesses, and the grounds. They need to be broken periodically and cleaned. In the rare instance that doesn't clear a bug, a sensor might be suspect, and if that fails, then the module might be suspect - usually a broken or bad solder joint.
Fourth, my V12 is two sixes joined at the crank. They are no more complex than any other engine. Where they get difficult is access in small engine bays. Sometimes that can be tough, depending on the job.
Fifth, a car that old - the internet knows all the known problems and the fixes.
Old BMW's - not my cup of tea, but it wouldn't scare me a bit. If you want it, go for it. Not a big deal.
edit: sisxth, if you're going to bust knuckles, might as well do it on something like an old BMW with a V12 - who wants to fool with a Honyota? Not me, that's for sure.
