Tires. I'm sure lots of folks perceive lower profile/stiffer sidewall as a sportier ride.

 

I got the g37x sedan wish I got the xs

 

Perhaps. But they're still just bread & butter AS tires, unless someone thought to put proper, high-performance summers on the car. Honestly, I suspect the stiff sport seats is what makes xS owners think their car rides any different than otherwise.

For me, the most noticeable difference between the two cars is the sloppy steering on the AWD. That, and the car's ability to launch hard on wet roads and snow. I've had a few AWD Sedans as loaners over the years, and I have to admit... the car is heroic in hard rain.

The xS is still a pretty car, 7AT notwithstanding. But I think it needs a set of swaybars, coilovers and performance tires.