[Kudzupatch]

I believe everything you mentioned is TBI, Throttle Body Injection. So your not really talking anything dramatically different.

Assuming a mostly stock engine to mid performance motor I don't see how you gain much if anything. The replacements will flow more air but you can also buy a replacement Holley TBI unit that will flow 600 CFm (if I remember correctly) and it is a bolt on direct replacement unit. That is plenty for most street engines.

You still have to tune the the aftermarket unit to get the most out of it. So why not learn to tune the existing unit? Replace the chip with a Moates Ostrich emulator and you can tune it from you laptop.

When I finally get to replace my engine that is exactly what I am going to do. Use stock TBI and just tune it to the new engine. If I need the air flow I will replace it with the Holley unit. Should be able to the do the same thing as the replacement without all the expense.

Not 100% sure but I believe you have to have a separate transmission controller with most of those. Your adding a level of complexity that unless you are really into the High Output motor I can't see the point.