I have read a lot of threads about the differences in these two cars and all of them say there is no change to Brakes, Steering, or Suspension. Just a larger diameter wheel and paddle shifters.

Well I have my 2011 g37x Sport in for service today and got a 2011 G37x non sport loaner. The difference in handling is to me night and day. The steering is slightly vague and the suspension is much looser and more forgiving even the transmission seems to shift more docile. The differences are obvious. So again I pose the question ...is there a difference? Sure feels like it.

 

Steering rack is different, brake booster is different.

 

Really?
My spec sheets and parts lists show the same steering rack (and 16.4:1 ratio) for the 2011 G37xS and G37x.
Same for the brake booster PN.

 

Do you have any mods on your cars. That can make a difference in steering feel. A front sway bar, or strut tower bar, or wider tires?

 

It comes with 18" wheels vs 17" wheels. The steering is definitely more tight follows grooves on road etc....not sure if it turns faster per crank on the wheel but it has more road feel. suspension snaps over bumps too like a sports car should. I just bought the car used as a Certified pre owned. Don't think it was modified but if it was I am glad as I like the feel. I guess it could just be tires but the tires on mine were the wrong speed rating and are being replaced so I would think they would be more mushy not less...they are Goodyear Eagle LS 2 tires.