sound system '87 mitsu pickup

alright, here's whats going o n, i do alot of work on sound systems.. on other people's sound systems, usually in sadan type cars. but as you k now a mitsu pickup doesnt have much space like one of those cars do. I'm simply pondering possibilitys of sound modification. I've replaced the two 3.5" speakers in the front with nice ones. thats a start, but no where neer my destination.

please if you have any ideas of where//how to better the sound system, including where to place subs etc. let me know. i'm sure i'd be able to hook everythin up, as long as i had a few ideas of where to put it, or how to incoperate it into the car, thanks

--~-gavin