I can say that the E34 M5 and E30 I got running with a buddy, the client/owner previously spent north of $40k with a shop for around 5 years to "Try" and get his S38 swapped E30 running.
Best part is it took us roughly two weeks get get both cars running and dialed.
Better part is he then went back to that shop after we fixed them.
WTF is wrong with people?