The fuel difference between bike or car carbs vs throttle bodies entirely depends on your milage and predicited mpg, i found under 6,000 miles per year with 14mpg worse on carbs i had the overall costs were around the same (taking into account extra cost of efi itb)therefore mpg argument is out the window.

The performance difference on rolling roads between carbs and throttle bodies are small too however how they drive on the road is different story imho only valid reason to go ITB its so much nicer to start warm up and drive.

I experimented with a few bike bits now if i was to go again i would not bother respacing bike itbs it only moved the torque around by small amount, power no real difference and 600cc bike pico injectors are fine on 2.0l zetec too.