As far as my experience since I used to own Rota G-Force.
If your going for looks I highly recomment you to lower the car on crucial, tein or any sort of spring and then put the Rota G-Force and you do not want to go over 245s for sure even with 245s you will rob a little bit on the full turn.

If you dont plan on lowering it then 255s should be fine but keep in mind that those rims along with those tires is going to be supper heavy .

here I got a pic for you just so that you can see how it looks with 18.x9 Rota G-Force 32offset with 245/40/18s and I had to roll my fenders as well .