Im planning on getting 4 Infinity speakers (62.7i and 60.7cs) which all have an impedance of 2 ohms each. If I get a 4 channel amp to power the speakers, am I able to bridge the channels to power a sub as well as the speakers or do I have to buy an additional amp? If I can, how would I do this? If not, is it better to purchase speakers with a 4 ohm impedance?

 

The issue that I see is not one of imdedance (ohms) but of volume balance.

You're going to have 5 (possibly six if you go with twin subwoofers) speakers and only four channels of amplifier. Bridging two of those four channels of amplifier gives you now 3 channels of amplifiers for 5 speakers.

You could run the speakers in series with each other left pair and right pair but then you'd lose the ability to balance front and rear volumes as they'd be driven from the same amplifier channel output. The two speakers - left front and right front would be wired in series to present a 4 ohm load to your amplifier and it will be quite happy with that.

You want to pick your speakers because of the way that they sound, not their impedance. If you picked you speakers for any reason other than the way they sound please reconcider your choice.

The easy choice is to add a second amplifier to your system - a mono amplifier or at least one with sub-woofer controls.