If one were to swap an ignition/FOB/shifter/ECM over from one Keyless Go car to a non-Keyless Go car, what all would one also need to swap over (Keyless Go command module, doors/trunk lid antennas..)? Would I find a non-Keyless Go but similarly designed control module/harness plugs allowing for plug and play, or would I be looking at a major harness splicing/joining endeavor?

'03 R230 non-Keyless Go car receiving '03 W220 Keyless Go car drivetrain/needed electronics.

 

No one like naysayers but the concensus here is the wording "plug-n-play" does not apply to Mercedes systems and particularly not to security modules.

If it works well enjoy it the way it is.
There is hardly a chance you can rework these systems modules to cooperate.

There's hardware level, there's software level and there's coding and everything needs to match up.

 

I appreciate the address, but do you have experience/knowledge regarding this specific system and proposed undertaking?

 

All right, don't take my word... ask @BenzNinja the expert who programs these cars all day long for living.
He may be able to work something to meet your special request.
🤞