http://minneapolis.craigslist.org/ra...680044419.html Read that. I was wondering if since he had that for his 91 S5 would it work for my 87 s4?

 

No.
Different AFMs between series, the S4 has a flat flange the filter would need to bolt to.

 

I figured as much. Thank you!

 

while clokker is mostly correct, he didn't mention that there are adapter plates that bolt onto the front of s4 afm's to allow a cone style filter to be used. now the next thing to point out is that you'll jut be sucking in warm air vs. the factory cold air intake.

 

Also, the one for sale is missing the attachment for the air pump hose, and the filter element is no longer fit for service.