Has anyone hooked up an amp to a non bose HU on a 07 G35 sedan,and does anyone have the wiring schmatic for wiring the LOC?

Just connect the speaker wires to the LOC, and get power, remote and ground from wherever you're getting them for the AMP.

If you need a wiring schematic for wiring an LOC, you probably shouldn't attempt it.

How do I know what colors the rear speaker leads are? What am I suppose to just guess or should I cut the wires until the rear speakers cut out. I mean come on.

If you have bose, then you'll just connect to the rear deck speakers for your audio source.

If not, the best place is just before the wires enter the rear doors.
For the right-hand side it's Blue and Purple.
For the left-hand side it's Light Green and Yellow.

The full wiring can be found in the service manual, gracious hosted by psedog.

http://www.psedog.com/cars/fsm/g35/sedan/2007/av.pdg