People that are experienced with car audio

One 8?

You need two 12's pussy.

Do you have an aftermarket stereo?

Goodness yes. A good deck makes all the difference. I used to be more into the car audio field but have not been into since I got ride of my Acura Integra. Crutchfield will do the trick but more importantly get it installed properly. Don't be one of those kids who goes all DIY and then everybody gets to watch as their door or floor mats catch fire.

Get at least a 12 or 2 10s

you can make an 8 pound harder that 2 12s if its the right one and tuned properly

ask

firstly, a new head unit is a MUST if you want anything decent to come out of your system. There are ways to get around buying a new h/u but unless you paid extra for a built in navi, etc. then its not worth the effort.

Next, yes any speaker and sub for the most part can be paired together because they are not connected to each other, they both feed into the amp(asuming that you are going to power the speakers from the amp, which i would highly recomend if you are replacing speakers)

Although that sub looks decent, i wouldnt recomend it if you want to use those speakers. To get any quality sound out of those speakers you will need to run them from an amp, and if you are buying an amp to run speakers, then you might as well run a normal 12" off the amp well your at it. Not sure if that makes any sence or not.

Are you on a budget?
if so, my priorities would be..
1.Head Unit
2.Good Amp (Min. 3ch, if you feel you might want to expand your system later on maybe look into a 4ch?)
3.Speakers
4.Sub

Like said above, there is tons of info online to help decide what to get.
I'm just starting to piece together a new system this winter, been out of it for a good 3 years.

Unless you already have an aftermarket head unit, that is a must.

If you want to run component speakers (separate woofer/tweeter and separate crossover) you should really run those off a separate amp.

That's a really low-end cheap sub. If you're going to spend for a head unit and speaker amp and component speakers, might as well either buy a better sub or downgrade the other components.

http://www.crutchfield.com/p_575P30010/Rockford-Fosgate-Punch-P300-10.html?tp=114#details-tab

would be a good option.

one ten with 500-600w rms, new head unit, new speakers and amp them. especially on newer vehicles, disconnect your negative battery terminal before doing anything. also what is the make/model of truck?

or you could have one 8 and have a sound system that is tolerable and sounds good.

seriously. 2x12s in a truck is WAAAAY overkill

you get what you pay for. and for the love of all things low frequency DO NOT get a fucking 8" 'sub'

inb4 has kicker "subs"

First of all, do not get any of the things you listed. Powered subs usually suck. You get what you pay for, if you cheap out, your sound system will sound like shit and it just won't be pleasant.

If your stock speakers in your truck are already fairly good, you don't have to replace those. Just get a sub to take out the bass so they won't get ruined. If they sound like shit, get new speakers

When buying a sub, don't just get whatever. You gotta look at the type of music you listen to. If you listen to a lot of rock with double kicks and what not. You'll want 2 10's because they kick faster and will be able to process both kicks. If you listen to a lot of rap and music with a lot of bass, you'll want 1 12 because it will be able to hit the low notes better.

If you don't have a budget, here are some things your should look into that will give you an amazing sound system for about $1500 max.

Subs:
10" Alpine Type-R http://www.crutchfield.ca/Alpine_SWR_10D4_10_Dual_4_Ohm_Subwoofer_p/500swr10d4.htm

12" Alpine Type-R http://www.crutchfield.ca/Alpine_SWR_12D4_12_Dual_4_Ohm_Subwoofer_p/500swr12d4.htm

12" Alpine Type-X (Only if you really don't care how much money you spend)
http://www.crutchfield.ca/Alpine_Type_X_SWX_1243D_12_Dual_4_ohm_Component_p/500swx1243.htm

12" Alpine Type-R Thin (Since you have a truck, this sub would be great, but it's pricey.)
http://www.crutchfield.ca/Alpine_SWR_T12_12_4_Ohm_component_subwoofer_p/500swrt12.htm

Check out the Alpine Type-S's as well. Alpine completely redesigned them so they are just as powerful as last year's Type-R's. Only get a Type-S if you get this years, don't get previous years. And stay away from Type-E's. They are just cheap and terrible.

Also check out the Kicker L7 or L5 series.

When buying an amp for your sub, don't get a multi channel amp for your sub. You won't get as much power to it as a mono amp. You don't need to power your speakers unless you want them to be really loud, then buy another 4 channel amp for your speakers. But for your amp, buy a mono amp ONLY!!!

This is a good amp for basically any of those subs.
http://www.crutchfield.ca/Alpine_MRX_M110_1100W_x_1_Car_Amplifier_p/500mrxm110.htm

This amp will give you amazing power to any of those subs. (This one is too powerful for the Type-S's)
http://www.crutchfield.ca/Alpine_PDX_M12_1200W_x_1_Car_Amplifier_p/500pdxm12.htm

When buying a deck, you don't really need anything special. You shouldn't have to spend over $200 on a decent single din deck.

2 of my buddies have this deck and its great!
http://www.crutchfield.ca/Alpine_CDE_134HD_CD_Receiver_p/500cde134h.htm

^ alpine fan boy?

Ahaha kinda. It's just most of my buddy's have either alpine setups or kicker setups so that's why I know the most about them. I don't know too much about other companies. I know Sony Explods suck. Those are terrible. Other small companies.