Do we trade?

[wallace david <wallace@mhd1.moorhead.msus.edu>]

My lovely bride, who is a traveling sales person has put 109,000 on her 
'90 100. She has maintained the car religiously and it runs great. The 
local dealer has a 91 100 with 37k on the od. They want 13,000 for it. Her 
100 has been serviced by the same dealer...Is it time to trade or should 
we put another 100,000 on the '90.

As an aside..I haven't been in a car that is as quiet or more solid 
feeling than our Audis..except for my buddies' 5 series BMW.