Just did the install today. Everything went fairly smoothly. Spliced into both left and right rear speaker wires at the head unit. Come to find out, the remote wire cannot be hooked up to a "switch" or "Accessory" wiring running into the head unit. The signal is digital instead of analog and will not turn the amp on. We had to hook it up to one of the switched accessories in the fuse box.
We ran the power down the drivers side floor and went through the wiring harness for the fuse box hole in the firewall. The speaker lines and remote went down the same path on the passenger side. I hooked my ground to one of the braces in the ceiling of the trunk.