To flash the VW ECU, you need ODIS on a laptop PC and the J2534 unit.
If you are replacing the ECU, you need the PIN to automate the immobilizer stuff.
Autel does support the ability to swap if you have the Pro versions like the MS908 with J2534. You wouldn't need to know anything technical other than possibly the PIN from the newer ECU. Cutting the anti-tamper rivets that hold the ECU in place is the hardest part of the process.