Short Version: Basically, I need recommendations for what was in the title.

Long Version: This is currently my very first truck, and I do not have a lot of money to spend at all. This regular cab truck was bought brand new by my father with no A/C, no power steering, no radio, manual transmission, and manual locks and windows. He wired the truck's radio completely by himself, running wires to the doors and to the 6x9's currently in the back. He gave it to me just as it was, and i put new pioneer speakers in the door, along with a pioneer reciever, but i kept the same wiring and the 6x9's. After that (this will make you think I am crazy), I put one of the two 20+ year old super pro 12" subwoofers he had as a teenager into my ranger. It came in a ported shallow box with an old motorola tweeter installed on the top, and a passive crossover to hook them up to inside the box. The box was meant for an older Nissan that was a smaller truck like my ranger I have now, and is made of plywood, and sealed with basic home silicone. I am still planning on putting the other identical subwoofer in the truck also.

At first you may think that they probably sound like crap, but most people that have them that i know get the same sound from two subwoofers that i get from one. They also had 3 month old pioneer 12" subs. My sub is also powered by one 300 watt Dual amp from walmart.

Basically, i want to know what the best box setup would be for my subwoofer, and what a good upgrade for my tweeter would be.

 

OK so to start tweeters belong in the front of the intended audience (you) as does the majority of the high frequency sound(small speakers). Having a majority of the high frequency in the rear is something like going to a concert and facing away from the stage. Bass is non directional and can be set anywhere while maintaining a forward or frontal imaging. This is why in home theater set ups the sub can essentially go anywhere. So tweeters should be mounted in kick panels or under the dash near the kick panels. Higher mounting will decrease imaging.

Second, with no knowledge of your sub my general advice is look up the manufacturer specs and it will tell you your recommended box volume based on three choices
1:sealed, small and fit in trucks well. Provide tighter and punchier bass, but doesn't develope -60 and below well in a small cab.
2:ported, larger than sealed and have port/s that may have tubes/baffles to extend the wavelength and provide more audible low frequencies.
3:bandpass, large combination of sealed on one side and ported on the other. Provides the most deep audible bass in most situations.