1988 Audi 90s: Opinions wanted!

[Johanna Bradley <bradleym@erols.com>]

I am looking at a 1988 Audi 90s that is in good condition but has rather high mileage (151k).  The 
body is in decent condition except for one shallow indentation on the driver's door and the paint job is 
extremely flat.  The interior leather is in good condition, all the windows work, and the sunroof works.  One 
ball joint needs to be replaced, one of the rods connected to the locks inside the passenger's door has broken 
making it impossible to get into the car if it is locked.  Also, the airconditioning fan belt has been cut.
	I testdrove the car today and it seemed to run very well.  There was a consistent whining noise coming 
from the back of the car (very soft, yet noticeable).  The lady selling the car said it was the new fuel pump.
	The following parts have been replaced:
	--3/98  Alternator, Starter
	--2/98	Fuel Pump, Fuel Pump regulator
	--8/96  1 CV Joint, one axle (used), one tie rod (all on RR wheel I think)
	--9/94  (with only 84,600 miles on car!!) water pump, radiator, timing belt, head gasket, valve job, 
		spark plugs

What I am concerned about is that even though many expensive components have been replaced four years ago, 70k 
miles have passed in those four years.  Will these parts last much longer or will I be stuck putting thousands 
more dollars into the car in a short period of time?  This is important to me because I am a student who 
cannot afford too many costly repairs.  On the positive side, I have heard that Audis last forever and are 
reliable.  ANY OPINIONS OR INFORMATION WOULD BE EXTREMELY HELPFUL!!!!  Thank you very much!
Jordan Bradley