Remember that the milage will drop off with lower (numerically higher) gears. 3.42 with 31 seems middle of the road, so if you are looking for power then 4.10, but milage will drop by @ 2-3 mpg. So it all depends on what you want. Also think about if you are ever going to put bigger tires on.
As far as descreening the MAF, it gave a little faster throttle response, a little better milage. I would do it again in a heartbeat.