Good question. I am trying to find out the same thing. Want to temporarily use my 124 wheels on my 107 so I can get the BBS wheels on the 107 re-finished. In my case- stock 94 E320 sedan 8 hole alloys, 15" w/ 195/65/15s on them. The SL has 15" inch wheels on it now, the only variable is the wheel offset. Earlier cars (107, 123, etc) had lower offsets than the newer cars (124, 140, 129, etc) but I'm not sure how interchangeable such things are- perhaps Luke at the Tire Rack would know? (I just ordered 4 tires from them, too. Upgrading to 16" wheels on my 124).

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94 E320
71 350SL