Engine Control Unit (ECU) Differences

Hello everyone,

Can anyone tell me exactly what the difference is between VW-Nr.:
028 906 021 FB and 028 906 021 B are both engine control units (ECUs) for the 1Z engine. The former is supposedly from a Vento, while the latter is from a Passat. The connector was slightly different, but I sanded it down, and the Passat connector fits perfectly. I've already driven with it. The car feels slightly slower (or at least I think so!), and it produces more smoke under full load. But otherwise, it works perfectly!

I understand that the Vento will have different control unit parameters due to different gear ratios, etc. But how do those parameters affect the Passat? Apparently, on the Golf 3, this device has the side effect of increasing power output by about 10%, due to those different parameters.

You're welcome.

Jörg.