I have 2009 base model 370z.
I'm trying to go either Yokohama or Hankook tire.
I have 18in rim and my tires are so skinny

(stock)
I want to go like 245 on front and 275 on rear or something. (fatter than the stock ones)
But I don't know how much fatter tires I can get since I have 18in rims.
Can someone recommend me good tires and how fat I can get to?
Thank you guys