or you can try what the supra/dsm guys do, get a 2.5" or 3+" GM MAF which users the blow-thru design so you can vent to atmosphere without the ill effects and also have the massive size. of course though you'll need a GM translator and I don't know if they have one for nissans' :/
I know someone who used the 300zx as a blow throu maf and it works great for him. it would save on trying to find that gm translator, (but i don't know how much they are so it might not be better). Just make sure you put it between your intake manifold and your blow off valve.
Yes you can eliminate your MAF, Just spend $1000 or so and get a power fc unit, but I wouldn't waste the $ if you have a stock Sr. Or even mildly tuned one,
Hey? PowerFC uses an AFM. You have to buy an extra module for it to support MAP