'91 200 Quattro brakes

[ericha@wrq.com]

I'm looking at a '91 200 Quattro with only 54K miles on it.  The previous two 
I've heard about in my area had 100K+, so this is great.  
During the test drive I noticed the classic front end shimmy from warped 
rotors.  I haven't been able to crawl around under the car enough to know 
whether it's got the internal caliper brakes or not.  Does someone want to 
summarize this all for me?  As I have learned from scanning the archives the 
conversion to more conventional brakes is expensive, but the car will have less 
unsprung weight and the rotors will warp less.  Other than frequency of warping 
what's the problem with the internal calipers?  Can't you turn the rotors?  Do 
they warp so often it doesn't matter?  What's the cost of replacing the inboard 
style of rotors with same if they can't be turned?

    -Eric Harman (ericha@wrq.com)
    '90 Mazda 626 Touring Sedan GT
    '91 Mazda Protege LX  --soon--> '91 Audi 200 Quattro