2005 dodge ram quad, louder bass?

I actually love car stereos in trucks!! By the way, I have worked on that exact same truck that you listed. (although the subs weren't under the seats) I understand if your not into spending a lot of money or don't want something too powerful. Everyone has there own thing and I respect that very much. Alumapro sells subs that sound awesome for pretty cheap, and they do have some shallow subs that will fill that cab with sound quite nicely. Not sure on the exact specs of the Alumapro sub that would work best in that truck, but I could look into that.  Another option that would probably be even cheaper yet would be to go with what dstang24 said. I've had some very good experiences with Rockford Fosgate. I still got some very old RFs in a series that they discontinued and they still hit after nearly a decade of abuse!!