Here is a picture of how I drilled the dash speaker cover area after installing my speakers. I created a drilling template using AutoCAD (a drafting program) and perforated the speaker area on the dash with holes. There are 169 1/8" holes in a grid pattern rotated 45 degrees, in each speaker area of the dash, although after drilling, I should have omitted one that came too close to the edge on each side. I modified the template, in case I ever had to do it again.
I then glued some black nylon mesh grille cloth (like window screen, but with smaller openings) to the back of the dash piece to help cut down on anything getting in from outside. It seems to work fine, and only reduces the sound output ever so slightly, like a factory speaker cover of like design would. More changing the tone of the music than the volume, which can easily be adjusted for with the radio's tone controls (I loose a little of the trebble end).
This took about 3 careful hours at the drill press, so as not to tear or crack the plastic while drilling the holes. I might re-drill the holes a little bigger in the future. [Peter Noeth]
