Care and feeding of turbos?

[Lynn Smith <lynn@dvcorp.com>]

I seem to be narrowing my search for a new quattro to the 200 models.  I've
never owned a turbo before, so I'm wondering what to expect.  How's it
behave while driving?  Is there a lag in acceleration while the turbo kicks
in?  Is a boost gauge standard?  Are there any user operated controls,
other than the throttle?  For instance, some Audi's have a switch to
disengage the ABS, can you turn off the turbo?

How about maintenance, is there any regular maintenance required?  Should
I expect a 200 to be less reliable overall than the same model 100?  One
dealer indicated as much.  What is the failure mode for a turbo?  What's
the cost to recover from it?

No doubt my ignorance on the topic of turbos in general is showing.  I
have a pretty good understanding of most of the systems on a car, but I
don't know anything about the principle behind turbo charging.  Anyone
care to give me a high level education?  How does a turbo wring out more
hp from those same 5 cylinders?  Can you recommend references for further
reading?

TIA,

-- 
Lynn Smith
lynn@dvcorp.com