First, thank for helping me about hub rings. However, to me it is still unclear.
I tried to contact the guy who sent Volk Progressive ME and hub rings 73.1/66 all around, but I could not get a chance to talk to him.
So, is there anyone who can explain why I need these hub rings? if I need these rings, are they perfectly fit my G?
Front 18/45/225
Rear 18/40/245
thanks guys.

 

Hub rings help center the wheels when they are mounted. Without hub rings you might bolt the wheels off center, thus causing it to vibrate. The circular opening in the middle sits on the hub. The reason why aftermarket wheels, most of the time use hub rings is because they are produced to fit a variety of cars. Different car makers use different hub sizes. Wheel manufactures get around this problem by producing a center bore and using rings to adapt them to fit a particular car. 73.1mm is a universal center bore size and a lot of manufactures use that so just about anyone can adapter them to their hub. The G35’s hub is on 66.1mm, so you reduce the 73.1mm with the rings so it can fit nice and snug on the hub.

 

why don't just go with 245/45/18 or even 235/45/18 all around? I don't see the point to stagger tires if the wheels are the same size. I think it would look and perform better with same size all around.

 

Plus you can rotate them anywhere on the car.

 

I agree, if you went with 235/45R18 all around your speedometer will be right on also besides being able to rotate your tires.
Should look real sweet.

 

I would get the same size tires.

The description above about the rings is perfect. I could not have said it better.