Just installed my Invidia Gemini and made a installation how-to for anyone thinking of installing a cat back system on a G37 coupe. It's pretty straight forward and can be done in a couple hours.

Invidia Gemini Cat Back Exhaust Installation, 2008 Infiniti G37 Coupe

Next up, HFC's. Just gotta figure out how to get the 3rd bolt out without becoming a contortionist.