Hmmmm... small enclosure, plenty of trunk space. You could run 2 8" subs ported on that 1000/1 and have some serious thump in a seriously small package. Look into the Sundown SA-8 and the Skar vvx-8. If you want one 10", there are plenty of subs that can take that 1k without breaking a sweat. The sundown SA-10 and Skar vvx-10 are two choices that have already been mentioned, and are proven performers. There's also the Sundown Zv3 10, but I doubt you're looking for anything that monstrous. Besides, that 1k would just tickle it lol.