Good info on the early V8s. many of the early ones had new motors put in them so early that they put the same crummy block back in. There are serial numbers that can ID the Alusil block from the Nicisil (sp). Every potential buy should have these verified.
I don't think BMWs have any more special tools than MB. Their repair procedures are often more difficult due to their emphasis on performance vrs ease of maintenance. BMWs also have been more in line with the Japanese with all their electrical gadgets. These complicated systems occurred earlier than on MBs and MB might have benefited from the industries experiences.
I have owned two BMWs. The first was a 74 2002 that I bought for my 16 year old daughter 10 years ago. My second is the 97 540i I currently drive. I have driven just about every MB going and none compare to this cars handling and performance. Some MBs might have the all out acceleration but none do as good at 100 let alone 120. It really is the "Ultimate driving machine". The 7 series cars aren't quite as nimble but are real road cruisers. I don't think they are any more expensive than a 140 "S" class to keep up. They would be a lot more expensive than a 126 "S" car.
Bosch Master, ASE Master, L1
33 years MB technician