More bang for my buck, but space saving too

ive got a 2001 taco double cab and im looking into improving my sound system. now ive been doing a lot of research on forums and other places, and im just trying to figure out what could give me the best sound quality while saving me space and money. ive looked into powered subwoofers alot, such as the Sound Ordinance B-8PT's and others. The only problem is, im not sure if ill be satisfied with the bass they provide. People talk about JL TW5 13 inch shallowmounts with high intensity amps but i dont want to drop that cash. i need a sort of happy medium with good sound quality and durability. What could be some other options that i could fit into my taco, such as under the front seats or behind the back? any info will be more than helpful!