Originally Posted by MadBill

Seems like some instances of opinion masquerading as fact here!
Some facts:
o -GM and others currently use the SD portion of the system for fast response and MAF for steady state accuracy, driven by emissions concerns more than performance.
o ~1990, GM issued a service calibration applicable to 3 or more model years, millions of V-6 Cavaliers, etc., to correct driveability problems. Unmentioned except to the EPA was the fact that it completely disabled the MAF in favour of pure SD calibration...
o -MAP calibration occurs at key-up, and every time WOT is used at low RPM. How many times per year do most of us climb or descend say 6,000 ft. without ever encountering those conditions?
o -If removing a MAF with integral IAT, it is as stated a simple job to fit a stand alone sensor.
o -Flow losses are cumulative. If you plumb in series an aircleaner, MAF and TB each of which "flows 'X' CFM", the system as a whole will flow way less than 'X'.
o -Most intake flow tests are done at 1.5" Hg. pressure drop. This value was chosen in the fifties for the then-new 4 bbl. carbs, as much to avoid the need to upgrade the OEM's flow bench motors of the era (which were designed to handle 2 bbls. @ 3" Hg.) as to match the then-typical intake pressure drop of an engine at high RPM WOT. It has no direct relationship to what a current EFI engine, with no dependency on vacuum-assisted fuel atomization, "needs".
o -An engine with a typically calculated "CFM requirement", [(displacement x RPM)/2] x V.E., will therefore, when fitted with a complete intake system rated at this same CFM, operate at peak RPM WOT with a pressure drop of 1.5"Hg./5.1 KPa This represents a restriction and hence power loss from an unrestricted state of 1.5/29.92 (5.1/101.325) or ~ 5%, a 25 HP loss on a 500 HP engine.

OK, I'm buckling up my flak jacket now...