Does any one out there know the difference between these two ECUs fitted to the MY01/02 Jap Spec STi.

Impreza 01/02 JDM STI 7 - AF480
Impreza 01/02 JDM STI 7 - AF481

Is it that one produces better power like the AE800 over the newer AE802 that are fitted to the UK MY99 & MY00 respectively.

Thanks in Advance