My car is a 1988 W124 230E 4M/T.

I'd like to escape from the K-Jetronic system because it isn't healthy now and the engine block has quite high mileage.

I'm considering swapping the engine to a newer EFI system, such as the M111 or M104 engines. But I'd like to retain the 4-speed manual transmission.

The transmission of my car is a 716.216 or 716.217 model with a single-mass flywheel, I believe.

Could anybody recommend an engine that could be mated with my drivetrain?

I'm interested in M111.970 from E 230 W210 because it's newer and fresher than M111.960 from E 220 W124. Is it compatible with my drivetrain?

Also, I'm considering the M104 of the E 280 W124 engine, but I'm unsure whether it requires more advanced modifications since the M104 uses a dual-mass flywheel and large clutch designs.

Please give me advice.

Keep the M102; rebuild or get a fresh one.
Install an aftermarket engine management system.
The input information required by later OEM engine managements makes them rather difficult to retrofit.

If you want to swap a 111 or 104 engine you can use the same flywheel it will fit those engines the problem is the fuel management