Originally Posted by Ed Wright

There is no advantage to speed density for a normally aspirated engine. None. A properly tuned MAF system is just as "snappy" as any other. Being limited to store-bought tuning software would make it a little more difficult. I have undone more of these deals for people than I can count. It comes down to understanding how GM uses the V.E. and MAF together.

It's very simple to make the GMs all-MAF like the Fords. Nothing to it, many tuners do it that way. (I don't) Not one thing wrong with that method.

Even worse than speed density, speed density-open loop. Don't get that one at all. I have yet to undo one of those and not improve both overall drivability and fuel economy.