[pope]

I just installed a cheap reverse camera in my BRZ last weekend. I don't know what the autohouseharness is, but my camera wiring is similar to yours (based on the eBay link).

The red and black wire is the power wire for the camera. Choose a key on/engine on source for red, connect black to ground. Any ground will work. I connected mine to the ground screw under the trunk sill plate.

The yellow line is the video wire. The red line on the yellow is to carry a signal to the radio for when the vehicle is in reverse, the BRZ should have no need for this. Ignore it. (Well, first find the signal check in the radio settings that shows "yes" or "no" for reverse, parking brake, etc. and confirm it switches between "yes" and "no" when shifting in and out of reverse; then, ignore the red line on the yellow plug).