I am doing an Accel dfi setup to my 930 with the carrera manifold and am probley going to go with the Ls-1 camaro throttle body and have an adapter machined for it. My reason for doing this is because the ls-1 already has the tps and iac on it and these sensors are compatible with Accel. For your application, see if the 70 mm mustang throttle body will have sensors that are compatible with the mega squirt. I noticed that the stang throttle body is a very close fit and may even be able to be machined to fit to the carrera manifold without an adapter.
86' 930/GT-40R Sold
94' Rustang GT daily