This is a slightly older thread, reviving in case it's needed for future reference.

ECU's can be bought, used and coded to your vehicle. Don't listen to Mercedes!!! But it is a lot more than VIN.

Beckmann can unlock ECU's, and I believe they can code them to your vehicle. Coding is a little bit more expensive I believe, but unlocking is $250.

Rudy, and I can do either as well. Not sure on Rudy's prices, but I can do unlocks for $200, $250 for pre-coded.

All any of us need is the original and the new one. I'm also not sure on turn around time for any of the others but I could get it done the day of, or the next day latest and have it shipped back out.

To expand on the options a little more, unlocking would be used if you have Star and can run "Teach in of Drive Authorization" to program the ECU to the various modules, key data, VIN, Immobilizer etc.. from an ECU in what is considered a "virgin state".

Pre-coded would be a drop in replacement or duplicate.