Some people seem to have problems getting the Bose amplifier to work properly when installing aftermarket radios, I have installed Pioneer decks in both a G35 sedan and G35 coupe and have not had this problem. Since all other wires are pretty much self-explanatory, I can only assume that people are not grounding everything the right way. To do it the way I've done it, you connect the amp ground wire from the 70-7551, the ground wire from the 70-7551, and the ground wire from the factory harness together. Ground this to the body of the vehicle.
Infiniti G35, G35, Metra 70-7551, Pioneer Z110BT, Bose, Z120BT, X920BT