Cost of ownership 126 vs.124

[A264172]

Iv'e had a 124 for about 5 years and have a pretty good idea of the price of maintaining the systems on it. But as it's rust issues make it less and less desirable for the long term every season, and not really worth the full restore as a more common M103 4 speed Auto 4 door. I have found myself looking at the variety of 126's in diesel and M103/M104 configurations (not really interested in the 126 V8's) as a possibility for the planned eventual move into a stead with less cosmetic issues.
In considering this, I dwell upon the potential for preimum pricing of the parts for an S class, and perhaps, systems that I am unfamiliar with from my 124 experience.

Any thoughts about what likley 126 maintainence items might suprise me as a 124 owner would be appreciated.