Hey Guys . Just bought my 08 g35x. First things first i wanted to get the 19inch rims on it.

Questions
1) Which size should i go with 19x8.5 or 19x9.5. (and What offset?) car is stock , it is not lowered. i plan to lower it after i get the rims
2) I want the tires to sit flush
3) what tire sizes should i go with ? i am thinking of a square setup since its a AWD i dont want to throw the AWD thingie on the dash
4)Also with the square setup what is the fattest tire i can fit 245 ? 255?

PLZ HELP !!!!