Originally Posted by luan87us
2 Ohm gives better protection with smaller gauge wires (aka factory wiring).
I don't mean to cause a stink, especially since I'm a noob to this forum, but the post I've quoted is incorrect. Using a 2 ohm speaker will actually increase the wattage going through the factory wire, not decrease it. However it doesn't matter, as the factory wire is more then capable of safely conducting 2-3 times the amount of power that most people will put to their door speakers. Also, using a 2 ohm speaker with the stock deck could potentially damage the amplifier circuit of the deck as it was not designed to run that low of an impedance.
The only rational reason to run 2ohm door speakers is to get more power out of the amp that is driving them. This does come at the expense of sound quality though as most amps will produce increased distortion at lower impedance levels.