And yes, I did a search, but didn't quite find what I was looking for.

I want enough bass to make the seats vibrate. Will one 12" sub do this? Also, if I'm getting enough sound from the sub, do I really need to replace the factory (xe) speakers? I know absolutely nothing about stereos, and I don't want to go to a stereo place and have them sell me more than I need. I'm really hoping to get by with a new cd player, and some sort of subwoofer system. Money will be a little tight once I get the truck,so I'm looking for the most bang for my buck.

Thanks,
Megan