Something in the spare tire compartment would be ideal because of trunk space but I'll do some research :) When are you gonna be in the Big D, JAR?

I bought the WickedCAS hideaway box w/ 13" JL shallow sub from a forum member on my350z. When I moved to a 370z, I trashed the 350z box (couldn't find a buyer) and hired someone in Austin to make a custom spare tire sub box for the 13" JL sub. The box you're looking at didn't exist then.

He did a great job, and it cost me $1k including two top pieces of carpeted plywood that cover the entire trunk area and act as a bezel for the sub. He also wired some new door speakers, matted the passenger door, and installed 2 amps behind the seats (I already installed the head unit and RCA wiring, ran power wire to the back, matted the driver door and installed and wired the tweeters). I thought it was a good deal in the end, mostly because he did a way better job than I could have with the box and saved me a lot of pain.

So at $450 to get you going immediately is not bad at all. But you can compare prices with a local shop as well. You might be able to get something a little nicer (like mine with the added top layer) for one or two hundred more.