I worked the SCCA Booth at this past week's Auto Expo, one of the members also working was a mechanic for a German specialty shop and another crew chiefed for a team running BMW's. I learned quite a bit talking with them, one of the tidbits concerned the Audi 4.2 V-8. The mechanic said the timing chain often needs attention between 75 and 100k miles even though it was supposed to last the life of the car. Since it is located at the back of the engine it is an "engine out" deal, 35 plus hours and around $10k cost............
If contemplating an Audi motor I'd deal with this before installing it into anything.
Then they got started on the BMW 4.4 V8....................:ah:
Audi Info:
Audi V8 Timing Chain Service: The Real Story - Redline Speed Worx (RSW) : Redline Speed Worx (RSW)