Originally Posted by FL 4Motion

I won't even attemp the math but if you plug your stock sizes into a tire sizing calculator, they're online, I like the miata one. You'll see that the perfect match for a stock 245/40/19 (stock fronts) but wider is a 275/35/19 and even a 265/35 is a bit short on the sidewall and the 255's would be shorter still (but a 255/40 would be too tall). Same with the back, stock nismo size is 285/35/19, iirc the best rear would be a 325/30/19 wider but same size sidewall. Now that size is damn hard to find and quite frankly, the Z has too much understeer built in with the stock 30-40 mm stagger (245 fronts, and 285 rears) so that rear tire won't work.

I'm personally looking to go with 275/35/19 fronts with 285/35/19 rears next go around to try to get a more neutral handling car, assuming the front tires won't rub etc with my wheel offsets (I have aftermarket wheels).