Lern me Audi 4.2

Dry sponge seeking any and all basic and hotrod info. Specifically manual transaxle applications as well.

My current level of research includes Wikipedia and YouTube exhaust clips. I know there are 32v versions and 40v. I know there are belt and chain timing versions.

Are there versions to avoid? Where are the pitfalls? Is mix-n-match required to get the best transaxle behind the best engine, or is it possible to buy just one parts car?

What about converting a Quattro trans to 2wd? You know, because reasons. Simple or no?

Obviously, asking for a friend.

I'm considering this for my 914 project as well, so I will be waiting to see what info is shared here. This to an 01E transaxle would make for a fun 2000# mid-engine track toy.

The timing chain version has become internet famous for eating tensioners around 100-120K miles.  Since the chain is at the back, that requires dropping the engine in an S4/etc.  This may or may not be relevant if you're swapping it into something else.

The early 32-valve DI ones have a tendency to crud up the intake ports valves because they don't get washed by the fuel.

I prefer the 0A3 transmission (out of the B6/B7 S4) to the 01E.  I don't know anything about the relative difficulty of converting them to 2wd though.

See above, timing chains and somewhat carbon build up. 

People have made crazy power with the belt 4.2 by using double head gaskets and keeping boost below about 80 ft-lb/cylinder, which is about the limit of the connecting rods.  Exhaust bolt pattern is the same as a 16v Volkswagen, and IIRC the passenger side head is a performance upgrade for the VW.

90% sure that the blocks are disposable items, the bores are coated aluminum and can't be bored or honed.  I don't think Audi even lists internal engine parts.

Besides the timing chain problems the 4.2's also have issues with cylinder bore scoring that makes them eat copious quantities of oil.  I wouldn't use one as a swap or buy a car equipped with one now.  They're all old and too unknown of a quantity at this point

So, did you buy it?