Funny you should mention that, I was originally going with fiberglass to maximize airspace, but in some later calculations, that mold design was going to push 4 or 5 cubes. I've never liked the sound of fiberglass enclosures compared to MDF, and I had more room than I thought, Not to mention the Fiberglass would've probably run me around 200-300. and a sheet of mdf is about 20 bucks, So i've scrapped the F-glass idea for a while at least, going with an MDF Box with less airspace. Already built it over the holiday, posting pics...