I'd do some research before using 8 gauge on a system that you've spent thousands of dollars on... The smaller the wire, the higher the resistance on the system. If you're pushing the limits of the amp, the thinner wire will put even more strain on the system. Hell yeah it'll work, but you will find that the amp will overheat much quicker, and you will be losing a percentage of your possible wattage output! The difference between the wire thickness is this:
4ft Length 8 gauge @ 2000WRMS / 2 OHM 1 Channel - 242WRMS (12%) LOSS due to wire resistance
4ft Length 2 gauge @ 2000WRMS / 2 OHM 1 Channel - 66WRMS (3%) LOSS due to wire resistance
So you can see, the difference is 11%. For maybe an extra $60 in power wire, having an extra 11% power and 11% more of a buffer when it comes to overloading/overheating the amp sounds like a good deal... Especially when you've spent probably close to $1500 on the amp alone!
Have a play with this to do some calculations for your own system:
http://www.rockfordfosgate.com/rftech/wire_calculator.asp