I used to put JL W-7's in people's spare tire well quite often when I was running my car audio shop. The JL stuff is some of the best out on the market and the W7 is an amazing speaker. A single w7 would keep up with most people's dual 10" rig... Down side is price and availability. A w7 alone is 300+ then the amp, box, cable, and instal... Your looking at between $750-$1K to get it done properly.
A second option is a pre manufactured custom fit box. They can be a bit pricey and don't always live up to the price tag so try to hear them before buying... On the up side, they take up very little space and look like a factory option http://www.crutchfield.com/g_530/Veh...ctorComplete=1 Sent from AutoGuide.com Free App