Soundwise, it is damn good. Not going to break any SPL with 1 10", but "carry on my wayward son" sounds bloody awesome!
When I measured the hatch area where I was putting the sub, I brought the bottom out farther than initially planned as that gave me the extra depth I needed to get the volume I needed. I'll have to find my book, but I took measurements of where I was putting it and estimated that I had to come x out from the side for the proper volume.
The sub is held in by itself pretty well, but I did two things that ultimately hold it in. I don't run a spare (usually, long trips I'll just toss it on top), so I put a mdf board and bolted it to the tire hold down...this is what I have my amp and cap on. On the passenger side of the board, I fastened a 2x6, planed, to push against the sub box. It is that 2x6 that holds the sub in place in addition to providing the right side brace for the lid, which I also recut using MDF. To get the sub out, I have to unbolt the amp rack, one bolt, slide it across, then the box lifts out.
I did the job with the trim piece in the car, next time around (want to better aim the sub and use a thinner fleece and try to get it to sit a bit flusher) I'm going to either take the piece out, or buy a junkyard one to do it with and use a mold release agent instead of masking tape.
All in all, it was the only option for me for a sub. Since I DD it during the summer, I need the space, but hate not having a nice strong bass component to my music.
The only other option I would consider is:
1) getting any old rear seats...the flip down sections
2) remove all the upholstery
3) create a mount for two 13" TW5
4) fiberglass them keeping the folding mechanism intact
5) give up on having rear seats
After everything else is up to par (in a few years) I'm probably going to pursue this path.