As a point if reference, these are the parts you would have to transplant:

https://www.ebay.com/itm/MERCEDES-W208-W210-01-02-E430-CLK430-IGNITION-SWITCH-KEY-EIS-ECU-ESL-SET/153870049592?hash=item23d35ea138:g:cQsAAOSwDwNecuOi

I am unclear about the wiggling switch situation.

One issue if you switch the parts: If you ever need a new key, the dealer makes them to the VIN# and you need the title. Otherwise you can send the EIS to someone on eBay and they can make a key.

You need a special tool to remove the EIS.

As far as fixing the one you have that's about $1500 if the dealer does it (or more). Maybe someone on eBay could repair it but I never heard of that exact symptom. You could inquire with Home (US) | BBA Reman

Good luck

__________________
1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra