Somebody's missed this one
Cheers for the bump :-)
There is no limit on what power the AGU ecu can control, all the mapping in the motronic 5 ecu I'd based on (ms) and fuel based on air mass which works out injection in milli seconds. The limiting factor is the maf scale which all the fuel and timing is based on, but if the MAF area is increased then the map scale window will in the same %. Then the tuner will need to dial in the load v the timing.
A lot of time is needed to set this ecu for big power unlike the me7.5 ecu. If your going to want the agu to run big power then the best way is use an electronic boost controller, and a wideband lambda LC1 system with gauge which can emulate the narrow band signal for the ecu, then all the ecu is taking care of is just the load based ignition timing and injection duration.
They best way to go would be Omex D600 ecu which allows for mapping based around MAP (boost) which means a mafless setup and more fine tuning control.
I have took the older motronic 2 ecu from the early 90s from 204bhp stock to 520bhp on a c20let.