there isn't much power in a maf upgrade on a near stock car.
But, if you are getting tuned its a "mine as well" situation, because you need to get the maf transfer function tuned anyway, so why not upgrade.
The 90mm maf will work fine for your car. Snoop around the lightning boards, alot of guys are upgrading their 80mm mafs to 90mm, and the 80mm's are going for dirt cheap.
I got mine with an airbox for 40 bucks shipped back in the day on my 95.