This looks like a great site filled with tons of info. I'm Austin from Ohio and I'm just getting into this audio stuff, which I really enjoy.
I'm very familiar with forums and have found they're a great way to learn about a subject. I drive an 03 Sport Trac which is a hard vehicle to deal with when it comes to audio equipment.
Here is a registry of my vehicle on explorerforum.com: 03 Sport Trac - Ford Explorer Ranger Enthusiasts "Serious Explorations"®
I have 1 10' Rockford Fosgate P3 shallow mount under the back passenger seat powered by a Rockford Fosgate 600 watt amp. I'm getting everything out of that sub that I can, and its has some nice bass for a 10'.
Although I love the 10' I think I want some more bass. Which I'll be starting a thread on that later.
Hope this is a good introduction!