In my 99 Z28 camaro, I took out my MAF, took it apart into 3 peices.
Took a hacksaw to the center part to remove that bar in the middle, then
use a dremmel tool to grind the nubs off that were left and made it smooth and round. Then put back together leaving just the plastic peice with the sensor in the middle. Car never ran too lean, actually on the dyno, the guy said it was "perfect" air fuel ratio.
And I could tell I picked up some HP from it... not much, but if I could tell, its something.