I have modified my MAF sensor resulting in stronger mid-RPM power, and just thought that I would tell about what I did. Looking at the MAS from the front, you will see a honeycomb-like material inside the areas where the air flows through. The purpose of these are to "straighten" the air moving through so that Karmen vortices are created, which are read by sensors within the MAS to determine the volume of air flowing through. I have found though, that this is a pretty good restriction, and if I could eliminate it, I would pick up a little bit of power. Everyone that I talked to told me that it couldn't be done, and that I would be ruining an expensive sensor in the process. I've found a way to do it.
Let's take a look at the sensor itself, so you can SEE what the heck I'm talking about:
I figured that in taking out the honeycomb material, the MAS would have some trouble because the air entering the area where the vortices are created would be turbulent. To combat this problem I eliminated the airbox around the filter, in my case a K&N. This is a VERY important step because it keeps the airflow as smooth as possible. After removing the restricting material from the MAS, I just clamped the K&N directly onto the base of the canister (the part which the MAS is bolted to) and made some aluminum brackets to keep the K&N from moving around too much.
The reason why this works opposed to some people who have just opened up the canister a little, is that now air is drawn through from ALL sides of the filter equally, straightening the air in the process. If you do this mod and keep the air canister, all of the air will be drawn in from only one side and will certainly make your car run very badly, or not at all. This has helped my mid-RPM power greatly with absolutely NO sacrifice in idling or drivability. I now have an FCON so I can run some ridiculously high boost levels, but this MAF mod served me well for almost 3 years.
If you think that the above proceedure is a little too drastic for you to attempt, there is another thing you can do to free up your intake and get rid of fuel-cut.
1) Looking at the MAS, you'll see the upper honeycomb(the big one for the main passage), and a lower honeycomb(the small oval-shaped one for the bypass).
2) You must unbolt the MAS from, the base of the canister to do this. Now take out the lower (SMALLER) honeycomb from the bypass passage. Leave the other honeycomb alone!
3) Now if you look inside the bypass passage, you'll see a small air "tunnel" running along the top of it. Inside of this "tunnel" is another restriction that you must get rid of. It's a little plug, which is pretty easy to see in the above pictures.
4) Now look on the OUTSIDE of the tunnel (right above it on the outside surface of the MAF, near the base of the MAF), and you should see a 3/4" diameter circular indentation filled with a silicone-like substance. Scrape all of the silicone out and you will find a 1/2" diameter plastic screw. This screw is blocking the flow of air through the tunnel, so you must back it out until there is NO restriction.
Here's why this works. Opening up the MAS by removing the honeycomb and the "tunnel screw" leans out the A/F mixture just enough to trick the computer into not fuel-cutting. Contrary to popular belief, fuel-cut is actually brought about by a rich mixture relative to the current temperature, altitude, etc...