personally i would replace it with another AUM you will have less work to do.
Im sure it is possible to put an AGU in, but the AUM has a fly by wire throttle and the AGU are a drive by wire.
If you changed the engine to an AGU you would have to change your ECU.
It depends what you are looking to do, many people say the AGU is better to get big power out of, but if you are simply trying to just replace the engine and keep it standard why create yourself more work

Thats my opinion anyways!
Where you based i know somebody who has 3 aum / auq engines.