Date registered: Jun 2012
Vehicle: 1998 E320 base sedan @ 160kmiles
Location: Boca Raton, FL
Mentioned: 79 Post(s)
Quoted: 1187 Post(s)
I do not believe you can just remove the IFI. Unless you circumvent the key authorization somehow, you will not even be able to start your car, as the authorization code is stored in the IFI (as well as RCL).
Regarding the transmission, there is a lot of communication between the TCU and the IFI over the CAN Bus, engine speed, coolant temp, selected / attained gear information, etc. The same goes for the other modules (Instrument Panel, Traction, etc.)