I cut out the entire bottom of the unifilter. (Have one if anybody wants it). Drilled numerous 1/2 inch holes to match the ellpitic of the unifilter. Just spaced the equally around the cut out in the unifilter. I also cover the bottom with foam mesh air condition filter to keep dirt out. With any increase in air intake I think you get a little more noise, but nothing dramatic. This set up ran well with 132 mains and 45 pilots on mine. Maybe could have gone to 135s. But im way past that now.
