If you swap parts from a with memory to with memory it will work ( or no memory to no memory ) I've tried to swap a 97 E320 memory motor to a 97 C280 non memory, physically they bolt up but electrically won't work properly.

Have a look at the parts catalog on this or other sites and compare part numbers. for 97 ish, 202 is C class , 210 E class , 129 SL class, I'd expect 170 SLK Class and 140 S Class to have a good chance of interchanging.

Taking the mirror apart is somewhat difficult to describe but not bad if you see a breakdown / look at physical parts.

Center the mirror using the adjuster switch ( be sure to do the same with the new one otherwise it will break. ) DO NOT fold the mirror housing fully forward as the manual says, the casting might break at the spring mount. Fold the mirror housing forward just enough to remove, unlatch the mirror cover clip. Fold the mirror housing back to the normal position. Pull the cover off to the outside of the car, be sure to watch the glass so it clears the housing.

The mirror glass is on a plastic backing, this backing has 2 clips ( sort of like a partial paper clip ) holding the backing to the round motor, unlatch these clips and remove the backing / mirror.

Mark the top of the motor, look at wiring plug location, these are interchangeable left to right but have different clock positions. Looking through the motor, you will see 3 screws, remove these and motor will come off, unplug the wire.

After everything is back together except for the cover, center the motor so the glass clears the cover as it is slid on.