Complete list of stuff I striped from the donor Golf when I pulled my 1.8L
for my van, the Jetta should be similiar.
1. Engine ; )
2. Complete wiring harness:  I pulled the entire thing all the way to the
fusebox, just to make sure I didn't confuse any wiring.
3.  Fuel pump assembly, I just mounted the whole thing, filter and all
under the van
4.  The vacuum storage tank thingy, on the Golf was mounted under one of
the main frame members in the engine bay.  I don't know if you need it, but
I plumbed it into the system just the same.  I think it allows me a few
seconds of power breaking when the engine is off, but who knows.
5.  I pulled the hard plastic fuel lines from the golf, that stuff is
usefull for various things.
6.  Charcoal canister, atleast in my case it looks identical to the ones on
the Vanagons
7.  Aircleaner assembly, some modifications maybe required
8.  Washer pump, again looks almost identical to the Vanagon, always nice
to have a spare
9.  If you don't have a tach, I hear you can wire these in instead of the
clock.
10.  The downpipe, so you can make a new exhaust.
11.  Any little check valves and such from the vacuum lines.

I think thats everything you would want to pull from the donor or atleast
everything I can remember.

Dave K.