Well, I pulled all my stereo crap out of my GT, but I'm hesitating on putting it in my Cobra. The main thing is the weight, those MDF boxes are heavy. So I got to thinking: when I worked in car audio years ago, we frequently put plexiglass windows in high end sub enclosers. Assuming it's lighter than MDF, is there any reason why I couldn't build a complete box out of plexi? I know it's stronger than MDF, so 3/4" may not even be nesessary, saving even more weight. What I don't know is how a plexiglass box would sound compared to the traditional MDF. Thunderforms are made from ABS, I'd think it could only sound better than that, right? Anyone with [more experience than me] in the business know why this would or wouldn't work? Would it be just as heavy? Or, do you have any other suggestions for a lighter material than MDF to make my box out of?