what is the wide's that you can go with 18x9.5 with a 56mm offset i would like to run 275/40/18 all the way around but i dont know if it will rub

 

I'm assuming you have a 4th Gen? Might want to add a "signature" with basic info about your car.... year, tranny type and any major mods (like lowering)..... that will help people answer your questions accurately.

The tire will fit fine on the wheel, and it will sit in the middle of the wheel well, so its not likely to rub on anything. If there is a problem, it will be because the 275/40-18 tires (26.7" diameter) are too large a diameter, compared to the stockers (25.7" if your car came with the Z-rated tires). A 275/35-18 or a 285/35-18 would be a better match.