new to car audio, 98 silverado

Hey guys, I've got a 98 Chevy Silverado ext cab. I'm working on getting some subs put in it within the next month or so. I work at Best Buy so I get pretty good deals on several things, but I was considering getting 2 10" Kicker l7 Solobarics Each sub pulls 600w RMS and each requires at least .66cuft of air with 1cuft max. I've managed to design a box that fits under my back seat that is sealed and I can pull almost exactly .95cuft of air out of it. As for the amp, I'm getting a 1500.1 Kicker Mono. Now for the questions, I'm wanting to be able to listen to anything from heavy metal to hip hop, so I'm wanting to generate as much SPL as possible, so is there any changes to the current set up that can help me out with that? Also I've already determined my stock alternator is probably too weak for this, so what size alt should I get for it? Final question, if I'm running 2, they come in 4ohm and 2ohm, so which series should I get?

Current Info: Vehicle: 1998 Chevrolet Silverado. Extended Cab Deck: Single Din Kenwood Ipod Deck Speakers: ---Fronts - Kenwood 6 1/2" ---Rears - Stock ---------------------------------------- Plans: Subwoofer Enclosure: 2 Chambered Custom. Dual 10". .95cuft per chamber Subwoofer(s): Kicker 10" L7 Solobaric x 2 Amplifier: Kicker 1500.1 Mono Capacitor: None Alternator: Undecided

Decibel wise, what can I expect from 2 10" in a sealed .95cuft enclosure?

i have the same truck and i've tried every possible combo of amps, subs, enclosures, etc...... @ the moment i've removed the rear seat and built a dual 15 box (upfire with 4 cubes net per sub, slot ported tuned around 30hz). I've also chosen an amp and sub combo to run a 2ohm load because its far less strain on the electrical system. I will be totally honest with you by telling you that you will not be happy with yhe choice of subs or the enclosure and probably no love for the amp either. i've ran the exact same set up with the exception of my kx1200.1. just wanted you to get an honest opinion before laying down some serious cash....