From trucks I have seen, there is plenty of room behind the seats of a Reg Cab dodge for amp and whatever subs you want, I would suggest either goin to souddomain.com and looking around for intalls, or goin to dodgetrucks.org or dodgetalk.com, places like those to see what other people have done, you would be suprised with the creativity people use. I have a 2003 Quad Cab Dodge myself and I am about to fiberglass the rear under seat storage for some subs.