oh, ok, I thought that there was a small blockage where the actual sensor is, but when turned around there was nothing. oh well, everybody is wrong every once and a while (this was just something I have heard, but not a solid fact anyways)
Thereis a hole for the air to go through and a small blockage, which is the actual sensor. Rotating the maf does not change anything, because your just spinning a circle. Now if you flipped it over, that would be changing things, but the sensor wouldn't be facing the airflow, which I would guess could cause problems.
Timing's already at 17°. I've seen several rotated MAF's with CAI's, and am just curious.
Something to ponder, though: If you orient the MAF in such a way as to place the portal on the outside of the bend, the air should be moving slightly faster than the air on the inside of the bend(sensor). The difference is slight, but there. Fluid dynamics at work, but to what gain? Oh well, the things I ponder.....