Originally Posted by CirrusWRX
Heh - stumbled on this by accident. I'm almost 100% sure (don't you love that phrase?) that auto and mt's use the same ECU - it's the transmission plug that is different, and thus, "tells" the ECU which mode to operate in.
That would make sense... it's not really conclusive evidence, but Cobb's Accessport maps don't differ for MT or AT cars. In fact, the "stock" map stored in an Accessport is supposedly based on an AT WRX. Seems reasonable that the ECUs are identical and the presence or absence of an automatic trans determines ECU behavior.