Personally, I would make the box for a single 12, as big as possible and run an Adire Audio Shiva. Great SQ, good output, and doesn't need a huge box to work. Plus, it makes good excursion at lower power levels compared to most subs. They are found @
www.adireaudio.com in the Car Audio section. They are $125 shipped, and should fit your needs nicely. Also, make sure your amp makes RMS power at 4 ohm, as the Shiva is a dual 8 ohm driver. I would get something like a Profile Clarus mono class D. You can get rougly 400 watt x1 Clarus from Crutchfield for like 100-200 bucks. And for your question between sealed and ported, sealed sounds tighter and more musical. Ported provides a boost at a certain frequency, such as 60 hertz, and a sharper drop along the playing frequencies. Ported is for the boomy bass that you hear most ricers playing. I prefer an ABC box, but you don't have the room for one of those. It takes the best of the sealed box and the best of the ported box, and puts them together. If you have any questions, feel free to PM me, and I will get back to you. Laters.
