I do not think I could name one good aftermarket MAF, they are scams. So what they do is for magazines and newbies too sort out and the rest of us to know enough to not care.

Far as why the screen is there and the fact that some OEM MAFs lack a screen that has too do with the tract leading up too the MAF. If it is straight and the flow would be evenly distributed even GM will leave the screen out. If it has a bend or the like right before the MAF like oh say a MAF mounted right too the airbox then it needs the screen to balance the flow across the whole inner area otherwise one wire could see much more flow than the others causing inconsistency in readings.

Now do some of us have intake tracts that are stright enough in front of the TB for the screen to not have much straightening too do, sure, BUT removing it gains nothing or very close too it so why bother.

 

The only aftermarket MAF that I can think of is the Granatelli. They had so many problems with them NOT providing the claimed HP gains (for the ridiculous cost of $300+), that they now ask you to select a model based on whether you have a "CAI" or not, apparently further revising the already modified calibration of the sensor, based on the fact that many people do not use the stock air intake ducting. Even they recognize the the ducting affects the calibration.

The Granatelli does not alter the ouput signal by removing the screen, they supposedly alter the calibration electronicly to under-report the air flow at high flow levels, leaning things out. But it doesn't work very reliably, because of the erratic flow conditions. Why pay $300+ for a "performance" MAF, when any good tuner can accomplish the same gains, more reliably, for about 1/3 of the cost?

 

The reason it feels like more torque is the throttle spring is more tighter than stock and when going downhill the car feels like it,s missing(again because of the spring!) Also the factory plastic cover for the spring no longer fits and the cruise control cable needs modification .I also liked my 48mm one better and will be reinstalling it come spring with a SLP airfoil that will do the the same as the bigger t.b. BTW i watched some 4fth gens running in STOCK ELIMINATOR @a NHRA RACE and they were running mid 11,s with the stock 48 mm t.b and are not even allowed to run a airfoil .

 

A lot can be learned from a stocker. Record in C/FIA 10.68 124.20 04/04/06 '98 Chevy Camaro