Newbie's neglect

[David Ratner <davidr@cdplus.com>]

I'm a proud '84 4000S owner (94K miles).  However, over the years I am 
asahamed to admit that I am the master of neglect.  What can I do to my 
beloved car to make it last my lifetime?  Is there anything to preserve 
the differential, or transmission, etc...  I am talking about inexpensive 
preventional measures, and things that I should look out for that can be 
potentially hazardous to the life of my car.  

How do I turn off the OXS light w/o replacing the costly sensor unit 
itself.  Any suggestions to help a cash-starved Audi owner would be 
greatly appreciated.

P.S.  In anticipation of my turning over 100K, I was wondering where I 
could get a grill-badge to mark this.