oh, james you just had to open this can of worms again didnt you?  :<)
y'all know my opinion on this.. ive used these wheels on vans for years, same
w/ many other listers, never had a problem.  dont knock it till youve tried
it.  plenty of info in the archives and i suspect BenT will chime in too :<)
heres the answer again:  NO.  they arent unsafe.
yes, they require machining of the centers and or spacers - depending on
whether or not you have a Syncro. depending on what style and size and offset audi
wheel you might or might not have to machine the center hub hole. folks
remember now the 100cs and A4/A6/A8 wheels will also work too, not just the
5000/200 turbo wheels. so there are alot more styles and sizes..15"..16"
...17"...lots more to choose from than a few years ago.     spacers are not a bad thing -
it depends on the type of spacer and the thickness.  different audi wheels
have different offsets. i have used around 8-10mm spacers up front for some audi
wheels, depending on the offset.   you just need to space it out so it clears
the control arm. you will also need to use longer lug bolts  - the stock carat
alloy lugbolts will do fine. you dont need to use spacers on the rears..  you
can if you want, but then youd have to install longer studs..   ive never
done this as its not really necessary.
are they strong? once again there are different audi wheels..but theyre just
as strong as any vanagon wheel..  give me a vanagon alloy, i can bend it just
as well as an audi wheel.  except the audi Fuchs alloys... those are forged..
hard to find tho.. strong as hell..they were used on the rally quattros..

chris