I just bought this 2012 G37X and slowly made some changes....those being tint and LED bulbs (interior and fog). My next add will be wheels and I am still trying to decide on 19" or 20", likely in hyper silver. I am not looking to change the suspension.

 

Welcome! If you plan on adding wheels but keeping stock ride height I wouldn't suggest going over 19's, you'll end up looking like a 4x4 pickup. Good luck!

 

Is 19" okay without change ride height? Or am I better just going to 18"?
Thanks in advance!

 

If you plan on keeping stock ride height I wouldn't invest too much in wheels. Maybe look for a set of coupe 19's.