There is a few "tricks" which can be used against auto ECU's to run a manual gearbox, but it cant be done the other way around (trick a manual ECU to run an auto)
If you are converted to manual, you wont have any issues (but one) to run a powerFC. The issue that i came across was the ecu plug on the engine harness. Now, ive HEARD and mercury said they could supply me a power FC to use the stagea harness, but i assume this was a r34 GTT one. Well, there is differences in VVT 33/34, so i dont know how good that would work and ska doesnt know what model PFC is in his car.
I have bought a r33 s2 stock ecu with the plug from japan, ill chop the engine harness on the stag and the replug it up, to suit the r33 gtst PFC i have.
The attessa ECU only needs a few ecu outputs, which are on the gtst anyway. (engine throttle position, car speed and something else)....sooo in theory, my method will work....just need a damn gearbox now !