the SL's have an offset that will not work on the 124's maybe a 500e but I doubt it.
The offset is 31 on my coupe as I recall, I have not had them off the car since last week when I installed a set of slotted rotors on the 500 and a set of OEM rotors on the 300. When I fit the new wheel I will check what is on the car. As it sits, it is a little froggeyed as it sits with the wheels as far out as they can get. Tastefully I might add.
Have you ever thought about an SEC? Check out the site MBcoupes.com and check out the 32valve 560SEC.
http://www.mbcoupes.com/memberscars/T/satishtummala/satishtummala.htm It was tough for me to buy a 500E except for the fact that I bought mine with 56k miles for a good price as I was looking for one of these.