When I said cheaper, I didn't mean cheaper brand. I just meant since the setup isn't designed for clarity or SQ, but rather loud and hard, you could have saved $100 or so and gotten the pair of enclosed Boston Acoustics G1's...$140 for 10's, $150 for 12's. They'll gladly take the same amount of power as the RF's.
But hey, whatever, it's about what you want and what you think will sound good so I hope it works out for you. Hell of a deal for under $400 to get all of that though.
Would you mind taking a pic of it in the car to show how much space there is left?