I've built half a dozen boxes for F-bodies over the last few years.

I've done a single 10", dual 12" and single 15" boxes.

Matter of fact, I have a box for a single 15" sub sitting in my garage for sale right now.

 

i had two 12's that hit harder than 4 tens. like everyone else is saying the enclosure makes the system. i now have a 3000 watt 15, 20 farad cap, 180amp alternator, in the back of my f-body. now that has already blown the seal and the trim off of it. i dare not turn it up past half way, my back glass already flexes. but once again it comes down to the ports, enclosure size, and the angle that the sub face is compared to the back glass, whatever its hitting against. i build all of my own stuff, and used a few other boxes. the one i built(im using now and will never go back) has the bose sound wave technology in it. it took 3 weeks to fabricate the ports. but now it has won many a competition. whatever you do talk to a professional sound technician, ( i am one) and ask him what he thinks about the acoustics in the application that you are wanting to run, and go from there. it all comes down to the nitty gritty and what you are trying to get from it.

 

iam doing a single 15 " l7 in my 94 camaro gona take awhile to build the custom fiberglass enclosuer