I just bought an ecu to keep for a spare but realized it's not the same part number. I do know that it came from a 6 speed. Mine is an early 02 model and I believe the other was a late 02. The only obvious difference from my car was the other car had no sunroof. Any major issues? I can live with a few codes, but will it affect driveability? I want to have that new ecu flashed some time in the future.

A56-t08 is the one I bought and from searching it seems to be for a later 02 to 03. Searching by my vin on courtesy parts I get 2371M-5Y703RE.

 

Any 6 spd ecu is the same as far as functionality goes.