I agree with WC11.I'm no expert but I have run aftermarket car stereos for over 30 years, installed by me. Unless you are running a ton of wattage (+1000w)16g is perfectly fine. I am running components in front off an alpine pdx-5. I ran 16 gauge and it was quite difficult to run through doors. its not the rubber booty that is difficult, rather the bracket in doorjam that the speaker wires need to squeeze through. and I do mean SQUEEZE, even with 16 gauge. I cant imagine trying to snake 12 gauge wire through that bracket. take a looksie and decide for yourself