ZMAF or QMAF?

[Indo240SX]

I've heard of a lot of people using the Z32MAF out of the 300zx and I've heard of some people using the MAF from a Q45 on their SR20 motors. Why is this necessary? Which is a better choice? What's wrong with the original SR20 MAF? I've searched a good bit and haven't really got much info about this. Any help would be great. Thanks.

[stupid nissan]

after a certain hp the sr maf cant read the amount of air you need to make the hp with bigger turbos and what not that is why people upgrade them i think around 250 hp is the most you can get out of a sr maf could be alittle more or less though