What did you do to the G today?
I had the same thing so I shoved a couple of boxes full of bike inner tubes in between the rear seat and the metal bracing in the trunk. Noise is gone

How much did you pay, if you don't mind me asking?
Heres a pretty cool upgraded g35 fob key kit. But 50$ LOLOL 20 max if that.
http://m.ebay.com/itm/151249764684
http://m.ebay.com/itm/151249764684
Finished up replacing all my missing plastic rivets (in wheel wells) and put my fender liner back on. Also, greased my upper control arm bushings. Thanks to kinetix for installing zerk fittings on the UCAs. Now I can go thru the carwash again.
Its brushless and I just do it now and then as a touch up between handwashes. Always polish and wax too tho. No worries. Haha my paint looks great for 10yrs old. The spoilers getting a but dingey tho. Repaint coming in 1-3 years.
I spent about $140 on all the paint materials and painted it in my back yard lol, the bumper itself was originally 275












