what, no comments from you doc? you seemed interested in seeing pics yesterday... ;)

Why bother with the FC tranny its not going to be that much power for the extra work involved with installing an FC trans just find a fb tranny it will bolt right up and you dont have to mess with the tailshaft BS.

The S5 electronic mop has some inherent dangers if not setup correctly. If done wrong, the unit can burn out, a new one is more than 1300 bucks, and that is not a typo. On occasion, when the e-mop fails, it can take out the ecu with it, another expense. If the e-mop is replaced and the ecu has failed, the new e-mop has been known to burn out due to the failed ecu.

Another consideration is the differential volume rates that mops from different years inject into the engine. The oem SE mop does not inject the same amount when compared to the 4 different ones used in the FCs, volume rates are listed in the FSMs for the appropriate years, with the tubo engines injecting the highest volume.

If I were to run an S5 engine, the 1st thing I would eliminate is the e-mop, go premix and invest the cost of a replacement e-mop in a standalone ecu. If there was a simple way to hook up a rod from the throttle shaft to SE mop, I would install the Rotary Aviation pump with a remote pre-mix tank

I dont disagree that a standalone is a good investment,they are faster,simpler and easier to wire up.But again,like a carb swap, its gonna delete some the S5's unique qualities.
Pulling the smog gear will delete the airpump activated aux ports,which work much better than the exhaust pressure activated aux ports of the S4,especially when youve opened up the exhaust system and relieved backpressure.
And the S5's VDI intake manifold relies on input from the ECU to operate.Engine speed,load and throttle position will determine the VDI position,and a standalone might not be able to copy all that as efficiently as the stock ECU.

tranny would need to go with it too because the spine changes after 88, that or get an aftermarket flywheel and appropriate counterweight..