Steve Wall asks what tasks are within the capabilities of relatively new VW
mechanics, heavy on book learning and light on experience.  Unfortunately,
the books leave out a lot of the important stuff, as they assume that you own
a lot of "you need this once every 60,000 miles" tools, and they also assume
that you won't break off studs, round off nuts, and lose things.  Key issues
in my opinion that you need to think through are:
(1) how long can the car be off the road.  This covers a multitude of sins,
especially if the answer is nice and long.  Cars that need to be running on
Monday morning are bad targets for amateur mechanics.
(2) how much do you pay yourself to work in the garage.  If it's more than
35 cents an hour, there are a lot of projects that professionals can do more
cheaply.
(3) who can you get for on site consultation, commiseration, and third hand.
Settle for American car experience if that's the only kind of skilled inter-
mittent partner you can get.  I do almost everything alone, 'cause my neigh-
bors and relatives don't share my addiction at all, but there are cases 
where I've needed two jacks and two hours where one greasy friend and 10 min-
utes would have done.
(4) does the project leave the car rolling.  By this measure Steve's cooling
system projects are safer than the CV joints, since the wheels aren't involved.
(5) how likely is the project to kill you -- either from the brakes (e.g.) 
failing after your bad repair, or from the car falling on you during the re-
pair.
All of these items sound paranoid, but the effect of thinking them through is 
to work your way up appropriately from oil changes to engine swaps, without
missteps that cost money rather than save it, and more importantly without bad
experiences that put you off wrenching as a fun hobby.
B.