what he said. i think they are like 15 bucks at wallmart. think the biggest they have is from 1 4 guage to 2 8 guages though. not for sure
i actually ran another set of wire with a dual slot battery terminal since i only had 8 guage to the rear, but this is a lot more work if you already have heavy enough hot wire run already....
Dude, do it the right way the first time!!!! Go to knukonceptz.com and get one from them, they run about 20 dollars and you can choose your fuse rating, they are very slick and good quality. As for the battery question, first of all most people wont need a battery unless you intend to listen to the radio for a long period of time with the engine not running. Your car is pretty new so your alternator should put out pretty good amperage. I dont know what it is but im assuming at least 130 amps. Just upgrade your wire from the alt to the fuse block, from fuse block to battery, negative wire from battery to chassis ground, engine block to chassis ground. Change all those at least to 4 gauge. That should be all you need, if your lights dim badly then you can upgrade your alternator to at least 200 amps, they sell them at knuconceptz also.