It can be done and you don't have to change transmissions. HDDP built a track car and used an aftermarket ECU. I believe it can be done with the stock SRT ECU, but it has to be unlocked and programmed to your car. Unlocking can be done by Beckman in Atlanta and a mechanic with either Autlogic with the mercedes module or the mercedes star diagnostic system can associate the the ECU to your car. If you do the swap you have to remember to not just try to start it without first getting it hooked up to the diagnostic computer as the ECU will lock after the third attempt to turn the key.