Re: does size really matter?
First off....use what you have for now....start saving your money up. Then in a 3-4 months look into a system overhaul and upgrade subs, custom built box, amp, wiring, the works. what you have now works but if you're going to look into a bigger custom box, might as well wait a little bit longer and do it all over and make it outstanding. you'll thank yourself you did.
To answer your question. That box is probably tuned to the mid 40's for frequency. It probably has seperate chambers for the subs and they have their own small port, plus its a pre-fab so the bracing is probably non existent and it's not high quality. Port size, box size, construction, woofer displacement, bracing, all come into play with tuning. What frequencies you'd be primarily listening too and what the sub is optimized for. Most subs these days are optimal at 35 hz.
For your setup now, that box works. Don't put anymore money in that setup. Save your money up and get yourself a nice custom made box specifically for woofers you choose to buy. Get a solid amp to power them, good wire to suit your needs, a second battery depending on how much power you intend to run, some sound deadener for your trunk, and maybe a High output alternator if you are really serious to keep your electrical strong.
SSgt. Jason Nelson
Andrews AFB, MD USAF
Dealt with audiobahn, sangthing, 93 saturn sl2, basswiigee, goodstuff, HomeGrown, 06gtmike
HU: Clarion NX501 Nav Deck
Amps: C2 Audio Recon 1.6, Sundown SAX50.4
Speakers: MB Quart ONX216 Components - 2 full sets
Subwoofer: C2 Audio Threatcon 4 V1 12"
Wire/Battery: SHCA 1/0 OFC--Shuriken BT-80 and Shuriken BT-35
Alternator: Mechman 320 amp