Hi, Other than Airbags, whats the major difference between the 89 and 91 S4's.

 

Off the top of my head...nothing major but,

Steering rack - low friction seals - it does make a difference in effort
Power steering pump - greater pressure, lower effort
Front cooling flaps eliminated
RDK tire pressure monitoring
PSD in place of LSD (limited slip is an option)
Door seals have extra lip to scrape water
Full rear fender liners
Windshield side edges filled with foam material
I think there is a window down/up automatic mode
Minor changes to HVAC controls

 

HVAC change was addition of a recirculation mode. Odometer reset accomplished through the trip computer control stalk vs. pod-mounted "O" button ...

 

the '90 and on dash was less prone to cracking by design, and more sound deadening in the car.

 

All of the above plus, my 91S4 came with Design 90 wheels, 7.5" front 9" rear. Light weight (GT) exhuast. I think the shelf goes away when airbags are added. The extra lip on the door seals are only on the later 91's. Mine, #362 has it.

 

The '89GT and '90 and above S4s/GTs also had numeric temp notations above the given temp gauge bars.

 

Pedantically: an '89 S4 can be either a 5-speed or an automatic. A '91 S4 can only be an automatic.

Another difference: The airbag-equipped 928s have a thick knee pad (anti-submarine pad) below the pod that limits how far forward you can get your knees. Add in the fact that the extended steering wheel hub was not an option (AFAIK) after '89. These two lead to a more extended driving position on the airbag-infested 928s. If your arms or legs are short or if you like a close-to-the-wheel driving position you may want to try before you buy.

 

How about the dread tire presuure sensor thingy... what year did that go away again?

 

crap never mind... Bill was on the "ball" on that one.
However what year did it go away?

 

RDK went bye-bye in MY 94.

 

Really? Not on mine...