Hooking up new speakers. How many channels do I need?

Usually you'd want 1 channel per speaker for best options.

First of all you get stereo per two sets of speakers.

So IE: 1 channel for Front Right, and one channel for Front Left...so you have left and right balance control.

Then 1 channel for Rear Right and one channel for Rear Left. Again so you have balance control.

Also now if your deck supports Fading....you can fade front and rear. meaning you can lower the volume of just the rear or just the fronts by controlling your fader control.

Now if you don't care about stereo then you can use two channels and connect fronts to one channel....and rear to the second channel....

or if you don't care about fading.....you can connect both right speakers (front and rear) to one channel, and both left speakers (front and rear) to the other. this way you get stereo, but no fading control etc.

So my opinion get yourself the 4 channel amp.

That'd be plenty.

its up to u really. you can do both . but most of the time you will get better sound running 4-channel