Also use a grommet where you go through the firewall. That is very important unless you want a fire. The main fuse within 12 in of the battery. Make the ground as short as possible as said. These are good things to know even if you dont do it, so you can tell if a shop is doing it right or not. Just because its done at a shop will not guarantee that its done properly. Some places may cut corners just to get the job done quicker or cheaper. Also if you ever want to upgrade make sure the power is properly sized so you dont have to pull it out again and re run a bigger wire.