Most of you know what gauge I run for my subs. Don't care if it's overkill, at least it isn't limiting anything. Had a bunch of it left-over from a previous install.
YEA, you really need to base your wire size off of maximum current output of your amplifier. Some amps put out up to, and over 30 amps, 10 awg would suffice for this in a short run, but 8 awg would give you some "head room".
SO, as someone already ask, do you know what the current output of your amp is??