I don't think the m103 5spd fits the m104 engine. Check for posts about the c36 engine transplant into a w124 wagon. I think it is discussed in there. The clutch should be available as manual transmissions were common in Europe. Also I bet a 23 year old 238K mile car will need lots of maintenance. There are a lot of bushings that need to be replaced every 20 years or so. I do like my 257K mile 300e 5spd though.