right now im using 16 gauge wire for everything, my fronts need to have about 12 feet of wire....just a little to long for my cat5 diy wire, and i don't feel like making more of that again. im running a kenwood 7070a which i read in sound & vision puts out 132wattsx2 in stereo.
i think my 16 gauge is a little to small, is it ok to double up? so a total of 4 16 guage to each of the 2 fronts? ive got about 60' of brand new ofc 16g, and don't feel like going out and buying 12g or even 14g if what i have will work just as good.
Well it won't hurt, and in theory is a good idea, but am I reading you correctly - you're using CAT5 (computer network) cable? Assuming I'm either mis-informed or you meant normal 16g stranded copper wire, I've seen multistranded speaker wire for sale in home speaker shops so if they can do it you should be able to. As to cat5 8wire computer cable I have no idea, but it is still copper...
12g speaker wire is fairly cheap (so long as you don't buy name branded stuff). I picked up 100' of 12g clear shielded spkr wire @ homedepot for ~$30.
Using smaller wire would cause your amp to push harder (heating up) and your speakers to drive less (bass especially). Essentially you'd end up with poor sound and could in theory fry your receiver, but with 16g probably not. Probably just not sound as good and run hotter.