Good points. You could use any TB you want, since it's only an air valve. The problems come when the plugs don't match and you end up from splicing in the TPS and the IAC (3 and 4 wires each).

Plazo:
The Holley is self learning, Supposedly just like several other systems out there, but some customers have switched. Why else would they start all over?

30 minutes later after the above comment:
Well I've had my morning coffee now and I realized I came on a little strong against Holley. So I toned it down. I have not done the research to determine why the H systems sometimes seem to work just fine and other times they don't. I could say that about most systems - FAST too, since the FAST systems need clean power (direct to battery) and clean tach signals. Noisy power or tach and the engine runs like crap. Automotive electronics in general, bring a new series of issues to the party that can't be fixed using old school techniques. But I will make a statement that I think is fairly accurate: "If EFI were the same price as a carburetor - NO ONE would use a carburetor unless racing rules required it"!