Ok, here goes:
Tweets: Pyramid TW22M
-They are adjustable, which is helpful, as cthomp21 said, for the factory locations, to improve imaging. And using the Vifa Neo's with the angle mounting cup is too expensive (I'd like to squeeze everything in under $250, so my parents don't freak, not to mention I am about to /go/ to college).
Woofers: Goldwood GW-S650/4 (the 4ohm version)
-These are nice, they have the specs I am looking for and they are cheap. Again, Vifa or Audax would be nice, but simply not cost effective. I don't want to spend $80 just on two woofers. I may upgrade the woofers later.
Crossovers: Something off eBay, whatever crosses around 3ish kHz.
Amp: Something from JBL, probably the P80.4, mounted in the trunk. I don't want people bashing it with their feet, and it will probably overheat in the ideal factory location.
Wiring: Knu...something, still don't know which wires for what, considering this is the part that I know the least about (now that I understand crossovers).
Speaker wires to the doors: I am planning on piggybacking on the factory wiring already running into the doors. The thing I don't understand is why the wires can't just be run through the little rubber thing. If its a plug, then where are the factory speaker wires? My plan is to take the factory speaker wires and hook them into the crossovers, then do my own wiring to the components. On the other end, I plan on taking the factory harness adapter thing and then extending those wires (for the fronts only) to the amp, leaving the backs still plugged into the HU amp. Ill use the preamp outs on the HU for the amp itself so it has an audio signal, of course. Ill hook the sub up to the amp as well, when I finally get a sub.
Someone tell me if the above won't work/is flawed.
One other thing I don't understand (besides wiring), is how to get power to the sub itself. Do I run a cable (and what sort) directly to the battery? Fuses what? etc. etc. etc.
