S4 Advice

[Robin Gates <72355.650@compuserve.com>]

I recently posted a message asking for advice of buying a 90Q or an A4.  Several 
people suggested that I would be happier with a S4.  I am very interested in 
performance and was told that the S4 is much more easily modified.  Can anyone give 
me some buying advice on the S4?  Buying a new one is not in the cards.  What can I 
get in the used market for $30K or under?  Any particular problem areas to look for? 
What has been the reliability of the S4.  (I currently have, in addition to a 72 911 
Porsche, an 88 Merkur Scorpio.  I do not want to repeat my experience with the 
Scorpio which has not been reliable).  Any place else I could go for advice?  
Thanks.