For our Heavyweight I'm using 2mm copper bus bars, 8AWG on power busses (batteries to link, link to fuse, fuse to ESC and ESC to return) and 10AWG on esc to motor (we use brushless so each wire is seeing ~2/3rds duty of the 160A). I decided to standardise on EC5s for batteries and ESCs, and managed to find trinity EC5s for the ESC/motor connection. I bough these http://www.ebay.co.uk/itm/331267837473 (note: you will need heatshrink for these) and these http://www.ebay.co.uk/itm/331244976106.

For our link we were going to use an EC8 but found them to be too bulky. The Castle Creations 6.5mm connector is rather pricy but can handle the same current but is smaller. We used an XT30 for the pre-charge link to avoid corroding the CC 6.5mm connector.