Anyone running Pro-M mass air injection

looking for some feedback on the pro m mass air injection. Wondering if anybody here has used it. Looking at a dual quad for a big hemi and single for a smallblock. And before we get started. Both of my cams have too much duration for any of the speed density systems out there. Not even sure why there are speed density systems. I used to run 5.0 Moosewangs at the track. And 87-89 and first gen lightnings always had to be converted to mass air to run a decent cam. Both of my engines pull less than 3-4 hg of vacume so the signal is too weak for the quickie bolt on.