I have a 2013 G37xs sedan, stock which it will stay that way.

Yesterday I was looking at the 08-10 none sport coupe wheels but I keep seeing the 08-10 sport coupe wheels and I keep leaning back to that.

I read the best tire size is 245/40/19

I know I read a staggered set will work, but I will only purchase a square set for myself.

What square set would be closer to my oem sport sedan wheels (18x7.5 with offset of +45)?

The front sport coupe which is 19x8.5 with offset of +43

or

The rear sport coupe which is 19x9 with offset of +45

I am inclined to believe the rear as the offset will match my current offset wheel of +45 and the suggested tires of 245/40/19 are the oem size for the rear (so the tires truly match up perfectly with this application, even though the front with this tire will "work")

Question, with the coupe xs, what size wheels came with those?

As I asked in my previous thread about the 18" sport coupe wheels. Will adding these 19" wheels negatively affect what Infiniti tried to offer from factory, in regard to straight line stability, cornering and handling stability, and overall ride (I know slightly rougher ride but is it "that" much rougher)? Will the wider tire cause more tramlining on the highway?

 

no time now, but stay tuned

 

There's another wheel you may want to consider, the 19" G35 Rays wheels are a great option for your X. RexHavoc runs them on his X. These are 19x8 +30 19x8.5 +33. These will give you a nice flush fit, are very lightweight & strong since they're a true forged wheel, and can be found in the $700-800 range. These will also clear big brake kits if you ever plan on adding that.

The wheels you listed, the 8.5 +43 will extend out about 15mm from your 7.5s
The 9 +45 will extend out 19mm from your 7.5s.

I'd go with the 9" so you can have a better fit at the fender.
Might shoot a PM to Rex Havoc for info on his setup if that sounds like something you'd want.

 

Thank you for the info for the 19" G35 but that is not really the look I like.

Could you kindly assist with the drivability of the 19x 9" vs my stock 18x7.5" as if it extends out 19mm from my stock setup, which is not really what Infiniti worked up. Will this have any negative effect on handling, highway stability (tramling), overall drivability as a daily driver?

 

Going from a 225 to a 245 shouldn't have any noticeable increase in tramlining, some tires are more prone to that than others, Neal@Tirerack may be able to shed some light as to what ones are more likely to exhibit that.
As far as going to a less positive offset, runnign a bit wider track will give you a bit more cornering control and having more tire on the road (via a wider tire) will perform better under higher speed cornering within reason. A 245 width tire is a better match to the Gs power, in fact it's a very good choice as far as not having too much tire and not having enough.
I think you'll be very happy with that combo. The only negative would be the added weight, which shouldn't be too much, three to four pounds max. I'm guessing.

 

Sorry for asking all these questions, but I do appreciate all your help.

You wrote:
"The wheels you listed, the 8.5 +43 will extend out about 15mm from your 7.5s
The 9 +45 will extend out 19mm from your 7.5s."

Wouldn't the 8.5 +43 be the better fit for the factory setup as the extended out is small mm for the 8.5 compared to 9, when compared to factory 7.5? Wouldnt I want to keep it as close to the factory mm as that is what the suspension was made for?

Also, will I notice the car being a little more sluggish with either 19" due to the extra weight for the wheels AND the additional tire weight compared to 18"?

 

The suspension is very similar throughout the G line. In fact the optional tire/wheel packages that Infiniti offers are all wider w/ the 43 to 45 offsets. The suspension geometry won't be affected, and you may notice the extra weight a bit, but if you happen to upgrade to a better quality tire (I assume you have OEM tires) the improved performance from better tires will more than make up for the slight weight penalty.

If you were going to cell cast 20" anchors then you'd surely feel the weight penalty, but you're pretty much in a WIN WIN situation here.