Right lads you wanted part numbers:
AGU: 06A906018G (standard)
AGU: 06A906018F (Cruise control)
G is standerd, F allows cruise control. I remember discussing it with topher with his reply:
i doubt you'll find the F type, they were bloody rare.. i had an AGU with cruise but have never come across another one, it also uses a different ECU so i doubt it'll work.
aum won't work, as you need a cable operated throttle.. aum is fly by wire.
Hopefully that clears some things up, but an intresting thing may be whether the butterfly alignment motors could be doubled up as cruise control, with some sort of means of controlling it (not sure if possible, but a possibility - but then it also depends how much the alignment motor can actually turn the valve as if its only 25degrees max then it won't work.)