A steel front bumper and winch will cause your front end to sag about 3/4". Coil spacers of the same height can address that. That said, you can pretty much run 35" tires without doing any modifications especially if you run fenders that sit higher than stock. Depending on how much higher they are, you can pretty much run 37's with some minor rubbing of the rear fender liners at a full flex if you still retain them. You should know thought that you'll need new and wider wheels to run 37's.