I am deciding to do a build again. I found some FREE cheap, heavy, but looks stiff enough board to make a box for my 18 BTL's. I want to make it to where I can try and compete in SSNW class. So my height limit is 17 inches. It will be going in a 4dr 87 Golf. The back seats are going away and box will be behind the pillar all the way to the back which is 49 inches and i widest it can go is 37 inches. Subs will be facing up and slot port towards the back and will be also be facing up. I know subs will be right next to each other. I have some kind of bracing in mind for it. Should I put one sheet on the bottom and three for the baffle or make it 2 and 2? Also want it loud daily. Powered by Atomic 800.1d.