Does the catalog you looked in have a dimensional chart? Perhaps the sport ones are a bit shorter. Beyond that I'd think it is just a valving change.

As a side note, at least on the 97 C280 , the standard version takes upper control arm " A " and the sport version takes upper arm " B " . The " B " arm is also specified for the same year E320. So far I've not found out what the difference is, there are not many choices, stiffer bushings / ball joint angle / length to get more neg camber.