Shaolin

I am upgrading the sound system wihin my galaxy 2003 plate, i have a double din touch screen sony xplot DVD head unit and also a 15" roof mounted flip down screen so my kids can watch there Films on long drives away. i will be installing JL component Mids and tweets and i have a 10" sub but can not find a good place to install it without taking up space. Has anyone got any idears? Any advice would be greatfully recieved. Thanks