I had a 230E in Jakarta - that was a slow 124
anyway,
Things that went wrong:
The car was hard to start, I think it was a fuel pump/ fuel pump relay problem
The engine was slightly noisy but it's the way it is
Is the shifting really that rough? or is it just noticeable?
I've found that most 124s don't shift quite as smooth as .. say a Lexus.
other than that.. usual 124 stuff..
especially the A/C Evaporator..
http://buying.articles.mbz.org/checklists/124/
good to read.