Subs for my box
 

Hey guys....come spring, I'd like to add a nice sub to my Box. Not looking for volume - looking for clarity and quality. Ideally something small that will fit behind the seat. I've seen a few recommendations for the Kicker sub/amp all in one. Is that the one to go for or are there other options? Up here in Canada, that's one's about $600 on Crutchfield, so want to make sure it is truely the one.
Also like something simple to install. I've got an upgraded Kenwood touchscreen and some focals in the doors. Want to compliment those.

Thanks!

I'm 6 ft but my wife is short, so I put a custom box in the passenger foot well. Not sure what kind of space you have behind the seats, but JL Audio (very well respected in mobile and home applications) makes "pancake" style subs.

10TW3-D4 - Car Audio - Subwoofer Drivers - TW3 - JL Audio

I didn't go through all the specs, but see if a design like this wll work for you. I'd imagine other companies make such designs now, too. The other option would be a stout 6" driver behind each seat. Subs frequencies are low enough that they aren't as directional, but you'd likely want two sixes in a balanced setup vs. just one.