2004 Cavalier - right?
pcarroll:1. Is it worth it to amp the rear speakers? Could i get away with leaving the stock rears?
I think if you don't amp them, they might get drowned out by the front speakers. However, you could just run the front speakers and amp them and not even connect the rears - up to you.
2. My head unit is an AVH-P4000dvd. The problem is that there are only two amp preouts. I'm not sure how the preout that will go to the 4 channel amp in the front work. Will the amp need to use both preouts if I am going to hook it up to both the components in the front and the 6x9s on the rear deck? I plan on adding the sub amp later, so i don't know whether i can do this or not with only 2 preouts.
The HU has front pre-outs and a second set that can be rear or sub. If you only run fronts and a sub you are great. If you want to run the rears as well, I would run the rear speaker outputs from the HU to the rear speaker level inputs on the amp so your fader still works and you can control your subs from the HU.
3. Are there any amps you can recommend that would work with these speakers that are a little cheaper?
Profile HA1040 or AP1040 for the mains, Kicker ZX750.1 for the subs.
4. How hard is it to fiberglass a kick panel?
I wouldn't want to do it, but I've never worked with fiberglass before.
I did a little bit of research and realized that i will probably have to run the two components and the 6x9s in parallel if i want to amp all of them. So i was also considering switching the to an MRP-F250 amp instead and wiring it to give 100w rms to the front components only.
Not sure where you are going here. You don't need to run the components and the 6x9's in parallel to amp all of them. If you were going to do that, you don't want a bridged 4-channel amp for them, b/c it is not 2-ohm stable and would only be about 50W to each of them anyway. If you are only going to amp the components, I would get a 2-channel amp rather than a bridged 4-channel amp to do it.
If i do go this route, what will happen to the rear 6x9s. Will they still play music?
You could run them off the HU internal amp regardless of what you do otherwise.
HTH!!!
2002 Ford Focus
Sony CDX-GT410u
Sony XT-100HD HD Tuner
Stock speakers, no amp, no subs