M119 issues to watch for:

- Timing chain replacement (although most have done it around 100-150k as a preventative measure, I've never read any reports of one breaking) - around $1000-$1500 (I think)

- Cam Oiler tubes. All but the 1992 400E have plastic tubes - the back end of them can blow out causing tapping due to lack of oil. A relatively inexpensive repair, and not a rampant problem (possible, though)

- Wiring Harness

M104 Issues to watch for:

- Head Gasket Leaks - $1000 to $1500 to fix (I think)

- Wiring harness ( From what I've read - wiring harness replacement on E320 is more common than on E420)

Anything that I've missed?

I did a LOT of research on the E320 and E420 before buying the E420. Yes - the engine bay is more cramped on the E420, but the reliability fo the engine is such that it doesn't matter that much.

Now, the evaporator repair kicked me in the ass - to the tune of $2100, but that is a problem common to all W124s.

Good luck.

Troy
1995 E420 81k miles