The biggest change was in 1995 when mercedes changed the bumpers, lower body mouldings, skirts, grill, and the seat upholstery.
The second major update was in 1999, when mercedes changed the taillights, side mirrors and the door handles (painted) + muffler...
In the meanwhile mercedes had some other changes doe to the R129...but smaller and less obvious...
here are some pics of my 1990 300SL that has been updated into a 1995 model and wil be updated into a 1999 model once I can find the time:
the MBenz R129 pictures
greetingz,