18's on a 370z

Originally Posted by TN.Z

I would suggest 265/40/18 if you are in need of the extra 10mm.

265/40/18 are 26.4" diameter, and 295/35/18 are 26.1" diameter or so, 265/35/18 would be closer to a low 25" diameter and you could run the risk of confusing your traction control.

Have you checked to see how much the larger tired would increase your unsprung weight? If you need more grip, then go for it, but if you have enough grip as is then I would stick with the current setup.

I would personally suggest a 265/40/18 for the front and 285/40/18 for the rear. Should give you more grip up front and reduce some understeer (if you experience any)