1. Probably the upper mounts on the struts, cheap enough and straightforward suspension work
2. Possibly the switch or just the rocker cover, impossible to tell without cleaning and looking for fresh oil. Either way it's not a complicated engine.
3. If you have air pressure and the correct tools I know this can be done on other cars, the head however usually comes off for this.
4. I'd be checking for air leaks as a first port of call, split hoses, vacuum pipes etc etc.
5. Trim panel comes off very easily on these.
6. You don't breath in the gases when welding galvanised but just make sure any metal being welded is cleaned back to bare metal (as you'd do anyway) before welding starts. I've had welding done on my B3 and it was straightforward
7. Looks clean
8. Remember the standard VW set up was transverse engine/FWD as opposed to inline engine/FWD for Audi.
You may find this useful. Febi are OEM for a lot of German kit.
http://www.febi-live.com
