One 18, or one 15, I just don't think you've got room to build a proper box for a pair. Unless you find some that like
i have aroud 11 cu feet of air space in my trunk i know i wont be able to use it all but i can use a good 8 of it, 4cu ft per 15?
also i might be selling my amp with the 8's now so the whole 3k idea is pretty much gone and ill probably go with a 5k or so set up and get a alt and some bats.
If you want to go the 18 route i have an AQ hdc4 18 im trying to sell and i live in PA, im only looking for 300 bucks and 3k on it is a walk in the park. Also it is a dual 1 ohm sub so you could strap two 1500s to it perfectly. let me know if you have interest i can send you pictures etc, i live about 3 and a half hours from you so we could always meet up for a sale