[Murderjetz]

So I've been wanting to replace my stock speakers, because they suck. But someone told me that all aftermarket speakers also require an amp to power them...
is this true? can they not work using the car's stock power? I don't get it.

[TurboLX]

depends on the ohms and wattage the stock speaker puts out, if its the same range as the stock speaker, it should work fine, if its more, you might need to wire an amp to it

[Murderjetz]

ohh ok...makes sense, thanks!

[TheUNZippee!]

After market speakers do not require an amp to use them. It depends on what you are looking for. Typically, if you are starting off with an entirely stock system, and want to improve it, replacing the head unit first will yield more improvement than changing the speakers. This is because when you crank the factory system, and you start hearing distortion, that is not the factory speakers crapping out. That is the head unit running out of juice and losing it's capability to operate the speaker properly.
So if you plan on upgrading your system step by step cuz you're on a budget, always start with the head unit. You can buy the nicest speakers in the world, but if you don't have the power to operate the voice coils in them, they will sound like shit. And no factory system in your average car puts out much power. In fact the power levels even in most 'high end' factory systems can't hold a candle to even most decent entry level after market head units, let alone stand alone amplifiers.

If you do decide to go with an after market head unit, and plan on upgrading your system down the road, keep this in mind when you spec out the head unit. You will want a unit that preferably has separate front, rear, and sub level preouts. (RCA's) Having a higher voltage level on the preouts is nice as well, as amps run on voltage. The more, the better.