ok here's a dumb question, but when you make an enclosure like this do you use some sort of time delay/alignment so that all the woofers appear to be working as one and not out of phase?
you should look for an authorized dealer who has more than just the vanilla at&t banded phones. You could get a hot nokia or samsung with a serious camera-- 5MP, GPS, wi-fi and all that, and be able to use it on a cheap data plan.
pioneer ts-d1720c. http://www.newegg.com/Product/Product.aspx?Item=N82E16882117238
They were rated really well in CA&E. I just got mine in and will be sealing my doors tomorrow.
it could depend on how high you have them crossed...and at what levels you are running your subs... you may have to run 2 sets of comps or consider running a 3-way system so each driver isn't cover as much of the spectrum.
try the kicker's on ubid.com. They have factory warranties and they are cheap. Plus they make their rated power and then some unlike the hifonics stuff.
peronsally, I'd go with the JBL's. You have more cone area than either of the other 2 options, and they are about 400w each IIRC. Which means you will not need as much amp to power them.
http://jbl.com/car/products/product_detail.aspx?prod=GT4-15/230&CheckProduct=Y
not to be a hater, but are you sure your woofers are going to breathe properly with that thick of a baffle? The airflow around the back of the woofers could probably get pretty funky. And why not use plywood as it is so much stiffer than MDF?
Also, someone mentioned an alarm. You should get on...