Originally Posted by KensAudio
2 Ohm speakers aren't advisable, unless you're SURE your amp has been engineered to handle that.
The lower the resistance of the speaker, the more effect the gauge of the cable has. Power lost to wire resistance is based on the current going through it. Less resistance at the other end (speaker) means your demanding more current - which in turn means there's more energy lost to just heating up your cable.
Speaking of current, if your amp is NOT designed to go down to two ohms (per channel) you can easily do damage to your amp by demanding more current out of it than it was designed to give. This'll manifest itself in something internally melting or thermally destroying itself.
I don't know what is meant by 'protecting' the speaker from something the wire does to it... If a speaker is blowing out, it's most likely because it can't dissipate the heat that the user is pushing through it. If a speaker is designed to handle 100 watts RMS, and 300W peak, for example, then it's expecting to see between 100 and 300 watts, but not on a regular basis - i.e. only for transients in the signal (kick drum & snare drum hits, etc). Only a portion of the power applied to any speaker is turned into acoustic energy, the rest becomes heat - or mechanical damage. If it sees that kind of power too often, or too consistently, then it can't dissipate all that power (as heat) and will thermally breakdown. This implies the user needs a speaker with a higher RMS wattage rating (a higher peak rating will just result in similar damage again) - or an amp with a lower wattage rating...
Best of luck,
Great post! Pretty much exactly what I said but in better detail.
To the OP, yes running your amp at 2 ohm is perfectly fine, just not many people do it (for door speakers at least, subs are a different story) mainly because 2 ohm door speakers are not very common, or easy to find.
My best advise is to pick your speakers based on sound quality not whether they are 2 or 4 ohm. Yes 2 ohm will be SLIGHTLY louder, but it won't sound any better. You should go to a local car audio shop and listen to several brands of speakers and see what you like, and go from there.