They were/are all available in Germany with 5-speed MT.

The newer the engine the more electronics go with it. You can run an 80s 601 or 603 without electornics if you manually set the idle at some stable rpm. I don't know if the 602s are as forgiving. The 606s have throttle by wire so there's even more electronics to contend with.

The 2.2l 601 and 2.5l 602 were available in the US with AT or 5-speed. The 2.5l turbo 602 and 3.0l turbo 603 were available in the US with AT only.

I have no knowledge of the other 60Xs and CDIs.

Sixto
95 S420
87 300SDL