alright,a ute,your best bet for speakers is in the doors and kick panels.if you want to run a sub,go for pioneer pro series speakers,yellow cone ones,they are awesome quality,run them off a good alpine or kicker amp,like a 800.4 kicker amp would be perfect,how insane do you want to go into audio?
and how much money we looking at for installing and buying speakers,i could go on for ever and ever about your possibilities.
heres a few good brands,you don't always have to go alpine (Even though i have all alpine except for front speakers)
DLS(swedish brand)
MB Quartz(Awesome speakers!!)
Pioneer(cheap value) bos...actually,ditch that last one
Alpine(expenisive but worth quality)
Audiobahn(great amplifiers)
eclipse(ugly but good quality gear)
they are my top six chosen,don't go sony and that,because they will last you a good day or two until they Xplod so ditch them.have a good look around at them.
Also,if you want to go alpine Type R/type S/Type X speakers in the door,forget the idea,because they are designed to have extremely large magnets,very wide and thick,so they are hard to jam into your door,look into other slim speakers.alpine aren't the greatest for size.