Most of the early '80's AMG modifications were only cosmetics and suspension. The rear spoiler was standard on 500SL's. They put on 16" wheels, stiffer shocks (no longer available), stiffer springs, skirts all around and an AMG steering wheel. If you had the AMG motor there would be a 5.4 AMG air cleaner or something. I have seen it and its very noticable. Most were cosmetic and most of that sutff is unavailable now.
'85 500 SL With AMG Appearance Package.
1985 Mercedes 500SL Euro (Gray market)
1995 BMW 520i Euro (Gray market)
1992 BMW 525it Wagon
1994 Honda Del Sol Si