AAZ Engine: Get it registered for your VW T3

Hello,
I'm considering getting rid of the ailing JX engine from my van in the medium term and replacing it with an AAZ. There are installation guides available online... but what can I expect when I actually have the new engine installed?
Is it as simple as just driving to the TÜV (technical inspection center) and saying, 'Hey, could you do a check... oh, and I have a different engine in it?' Or does it involve more hassle and paperwork? And how much does it cost? Am I even allowed to drive there until the next TÜV inspection?
Perhaps someone has already gone through this and would be willing to share their experiences with me.

Thank you in advance!

Holger.

Okay, hello. As you already mentioned, you first need to go to the TÜV (technical inspection authority), which will then register the engine modification. You should also inform the authorities about the change, as the engine displacement has increased by 300 ccm. And you shouldn't hide the increased horsepower from your insurance company either.
You can, of course, drive the vehicle to the TÜV (technical inspection center) with the new engine.