On a '12 bike the ECU is mated to the bike via the VIN. You can swap ECM's from bike to bike, but there is a very good possibility of encountering issues. Keep your ECM with your bike.
I seriously doubt you will need a new ECM with a new motor, your's should work just fine. All the electronics from 2009-up 106 motors are the same so a '10 Vegas will use the same sensors as a '13 Cross bike. 2008 models had a different MAP sensor, so their ECM is different.
What happened to your motor?
The Vic Shop, Inc