At 13,000 miles it is already time for new tires and the question I have is can I put 255/40R18 on all four stock rims or are the front and rear rims different sizes?

 

the rear are 18x8.5 and the front are 18x8. I was thinking about going with a 235 in the front when I get new tires. This way it would look less stretched and fill the gap a little better in the wheel well. There are several people on here running 19x8 with 235 tires so I know it will work with our cars. I have no problem being the first with it on a stock wheel, but I don't need tires yet, so it looks like you get to be the first.
Please post pics when you get it done, I want to see how much better it looks.