Heck if you take your time and look at the used rims and tires you can get a great set for much less than that. Just make sure you run the same size front and back on the X. If you wanted 18" then the perfect tire size for the 07/08 X is 245/45/18 on a 8 or 8.5" rim.

 

God... I love this forum!!! ppl are nice! Thanks so much...

 

Here is an example of used set of 20s I would get if I didn't have my 18s already: https://g35driver.com/forums/wheels-tires/235538-selling-some-sedan-parts.html

 

There's nothing wrong with your OEM tires except they don't wear like
you might hope. I don't recall exactly which Bridgstones I had on my Z
but they only lasted 10K miles, at $1200 a set that's a poor yearly investment! If and when you decide you need new tires you can do better
than Cosco, like Tire Rack. I checked Cosco and was in shock at there
prices compared to Tire Rack. I was like, Hey I'm a member! Then I
discovered they won't install tires on aftermarket wheels....strike two.
Good Luck, Gary