any suggestions are accepted....
does anyone know what is the difference between this two engine types?
why does the A3 perform 15hp less than the A4?
can a A4 ecu solve this problem when installed in an A3?
has anyone have any ideas?
pls i am in desperated.....

More than likely the difference in the motors would be the head, ecu, and possible the tranny. The head being the main gain in horsepower.
I highly recommend that you do not do a headswap. I did a head swap on my d15b8. I replaced the head with a Y8 head off of a d16y8 vtec motor. the head gasket blew 3 times in the course of a 8 month period :banghead: .
At that time i opted for a JDM B16A :lol2: