aftermarket radio instal,and wheels offset..

[blues t]

Im new to this fourm.I have a 2007 g35 coup 6mt..I want to take out the radio and put in a aftermarket single head unit?is there any kit out their for this year or do I gotta do some custom work to it?also I am planning to get some work vs-xx 20in rim,suspension and camber kit for the car.planning to go 20x9.5 front and 20x10.5 or 20x11 in rear what is the best offset to go with and having everything flush with the fender?