Used 4.2L A6's going cheap-what's up?

[Mikea2769 at aol.com]

I've noticed many 2000-2001 A6 with the 4.2 V8 selling for $14-20,000, way  
below "book value".
 
Were these problem models? Any info on weak points is appreciated,  
especially regarding the tiptronic.
 
 
Mike  Aiello
87 5kcstq, 311k miles, orig.  owner