[Brett09]

I did car auto for a number of years and the only two ways to tackle that. One way is to buy shallow mount subs, which normally don't give most people the sound they are looking for. The other it to build a center console that goes from the floor and wraps up around the seat. You can get a lot of great sound out of the console at the expense of cab space. Just remember w/e subs you use need to be matched with there intended use. (I.E. sealed or ported and air space)

There is one last option and that's to start cutting into everything. In that case the sky and your wallet is the limit. If you need any help with ideas just shoot me a PM and I'll do what I can.