I have an '07 G35x and am purchasing a set of non-staggered 18x8 wheels.

I know the stock tire size for the OEM 18x7.5 wheel is 225/50R18, but since I'm going with .5" wider wheels, should I go with a tire size larger than this?

Thanks guys.

The same tires would be fine with the 18x8 wheels

Excellent, thanks for your help.

You could always upsize to 245/45-18. Only 0.7% off from the OEM size.

Are there any advantages/disadvantages from going with a larger tire size than the OEM 18" size?

Pros - more cornering grip.
Cons - more expensive tire, more unsprung weight (like a pound more per tire).