I dont really bore it straight through if that was what you were thinking I use a small honing bit on a drill and run it inside the front bore and rear bore of the maf sensor untill the side walls are about a 16th of an inch thick. Then I dremel all of the edges of the maf sensor tower in the middle to make it as small as possible so more air can travel through the center. Then I take out the maf sensor it self and use a straight boring bit in a dremel and bore out the maf sensor air tunnel where the sensor sits in and chamfer the edges. Then I use a wire brush bit and polish the inside of the maf sensor and the air tunnel, put the sensor back in and presto I have a bigger maf sensor which kinda made my gas mileage worse because the engine now uses a little more fuel with the larger amount of air that is traveling through. But it helped the throttle response quite a lot and I can feel more pull at higher speeds. Sorry for the long explanation.