haha! kevin, i'd like to go manual but then it involves clutches.. the clutch pedal which i dont have in any of mine and then it requires a good solid gearbox.
i thought of the gm4L60E because i thought it might be easier to get to work (being gm and only really being quite alot higher torque rating)
didnt they use the 5L40E on the last 3.2's?
I personally think the manual route would be much less work, granted that you'd need to swap the pedals with a manual car and add a clutch master cylinder, change the prop, flywheel, etc.
The problem with using a different auto gearbox is that the way the ECU drives the actuators is tuned to the hydraulic system of the gearbox and the ratios it uses. Assuming that all the sensors and solenoids are broadly compatible you could end up, for example, with an ECU that doesn't shift "hard" enough for the gearbox, meaning it'll wear rapidly.
Of course the ECU might just decide it doesn't like the ratios in the new gearbox and go into limp home.
I think a gearbox controller that you can tune or an uprated autobox that's not electrically controlled (or just has crude lockup and overdrive solenoids to worry about) are the only feasible automatic options.
I believe there were Omegas with the 5L40E but not in this country, sadly.

Kevin