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Eh. 160W CD receiver, 200W equalizer, two 210W 4"x6" and two 420W 6"x9". Nothing special, it's all Pyramid. But I'm highly considering buying a Pyramid 2000W amp.

Pretty much working my a** off at a minimum wage job and living off of nothing but the bare minimums and spending the little bit of cash I do have on my car. The sound system was only $150 because I went through JC Whitney. To get an equivalent system in my home town would have been about $600, so it was practically a steal. The engine work, paint job, and new vinyl roof I've gotten for my car since I got it (for free from my grandfather who had purchased it for $1 at an auction in Nebraska) has amounted to about $2700.

That's why I got speakers instead of subs, woofer, and tweeters. It's just easier, and cheaper, to configure it all for the right sound.

What you need to look into is getting two tweeters, mounting them in the front of your car, two subs, mounted in the rear, and four woofers, one mounted each side in the front and one mounted each side in the rear.
You would need to find an amp with all the appropriate connections of course, or get one amp to opperate the front and another amp to opperate the rear -- or have one amp run the left and the other run the right.

Or you could scrap the whole subwoofer, woofer, tweeter idea and just get speakers. Because speakers have a small sub, woofer, and tweeter in each one so that it maintains a balance between all pitches, but you need really good speakers if you want it to be loud then.

Yeah...well the RMS is what a speaker/tweeter/woofer/subwoofer or equalizer/amplifier can put out or handle constantly without any damage to itself.
The peak is what it can put out or handle at it's very highest, but playing at the peak for a prolonged amount of time will cause damage to the system.
The RMS in many older speaker systems was usually about half of the peak. In newer systems the RMS is usually about 1/3 of the peak, since technology has not assisted RMS capabilities as greatley as it has increased peak power, proportionately.

In my Pyramid sound system the 160watt CD receiver has a horrible RMS, probably only 40watts divided, so 10 to each speaker. The speakers have an RMS of nearly half their peak, so I need to get about a 1000watt amp so I can play it at it's RMS and reach the RMS of my speakers, for the greatest output.
With amplifiers, if you play them over their RMS they will often have a lot of unnecessary noise which interferes with the acoustics of the speakers, and that's annoying.
The sound system my dad has in his shitty red Nova puts only 12.5 watts to each speaker (I think it is rated at it's RMS power though, not the peak) and is MUCH louder. It pisses me off, lol! Technology hasn't come too far in sound applications in the past 20 years, though audio businesses would like you to think it has. The only one making impresive progress is Bose. When you take a look at my dad's Bose home theater system from 1987 and compare it to newer home theaters from other companies, it is still far greater in RMS, even though it peaks at about the same. But just take a look at the speakers...they are tiny, four 4"x4" speakers that put out more sound than the newest Sony systems with upwards of 8 speakers, all of which are much larger.
Plus, Bose can make surround sound with ONE speaker.
I like Bose. I want to get bose home theatre quality stuff and put it in my car, that would be tight, I would just need to route an alternate CD thingy to it so it would be skip-proof.

I don't have any recommendations off the top of my head, but check out www.jcwhitney.com in their audio section, you should be able to find plenty to satisfy your needs there.

There's a lot of options out there. I'm not so sure putting them in the bed would be a great idea, unless you've got a foolproof way to prevent them from getting wet, and most of your sound would be lost outside the vehicle, so really you'd only be "impressing" the other drivers and pedestrians.

Well there's always a lot of options. Heck, if you wanted to you could get marine speakers and not have to worry about the rain, but marine applications are just that, speakers, and they aren't the most amazing of speakers eaither. So that idea is out of the way already.