At least 4 gauge wire connected directly to battery. I ran mine sorta like Scott did but through the blower box, and ran down the passenger side of the car. I ran the RCA and remote wire down the driver side of the car. Use a ground less than 1.5ft from the amplifier, and most mount it to the strut tower mount. Be sure to properly clean the surface of any paint when applying your ground. After you have firmly tightened the ground down throw some vaseline on it and the bare metal. This will help to prevent rust as that seems to be a common place for rust.
I'm running 4 gauge wire now pushing 1000W RMS/3000W PK, and haven't had any major issues. I have however thought about upgrading to a 0 gauge as I may add another amp of the same range for another sub.
