If you are looking to run a 245 on all 4 corners then your tire choice is going to be limited and you will have to be cautious of the wheel offset you choose, but it can be done without having to roll the fenders OR add a wheel spacer. Check out my thread
here. I think anything beyond a 35 sidewall will cause fitment challenges. I assume you are looking for an extreme performance summer tire, right? If you are willing to step down a class in performance tires then you will have a few more options.
-Josh