my 86 5000 s has "cs" interior and options. i'm fairly sure it hasn't been replaced or modified because i know the people who purchased it new. it has "s" wheels, and it's certainly not a turbo (i know this because audi wants everyone to know where the turbo is by casting "turbo" on it in huge lettering). i was just curious.... it's an avant.
also, the vin says it's an "s" as well as the back of the car.

you have what is called a 5000S "custom." Basically you could preorder a base 5000S and add options from the CS if you chose to do so.

Also some 5000's showed up on the showroom floor with more options stock than others...

HTH!
Steve Ankney
88 5000
Holland, MI