I was looking to Maybe get another CE again, I had a 91 (M104) for a few years but ended up selling it. I had head gasket issues with the car, (replaced it once but started to leak oil again later). They said it had some electrolysis issues on the mating surfaces, because of the wrong anti-freeze being used (before me) & not changing it quick enough.
I read one time (in some Euro rag) that the 24-valve engine was never really a good design in that it had basically to many head studs (or something like that, as I recall) for the given area surface & therefore more suceptable to leaking & having head gasket issues. Kind of made sense to me, based on my experience with my car.
Anyway fast forward a decade, so I have stayed away from the M104 engine & am thinking of getting the M103 with its single OH cam versus the double OH cam for the above reasons. I know the 103 had valve guide & seal issues but read where this had been resolved by 1990? I know about enough on this subject just to get my butt kicked, as I always kinda thought that the old M103 single cam was more like the old standard MB inline 6 that powered the cars from the 60's.
For this reason I wanted to stay with a M103 engine when looking for a 300 CE, (seems like I'd rather deal with valve train issues rather than leaky head gasket issues, that really can't be resolved properly). I know head gaskets have been improved since 91, but they did install the latest & greatest in my 91 when done.
I know this is a long post, but have always wondered about this. Thank you for the opinions!