Will this setup work w/out fender mods:

R 20x10 +35 255/35/20

F 20x8.5 +35 245/35/20

I'm hoping this will work w/out shaving the fenders, the car will be on stock height?

wow, that close for no fender mod. i guess it depends on what kind of tires you're going to be using since some brands are not as square. stock height? it may look werid like a 4x4,

Don't put on the wheels yet if you're going to be at stock height still. Also, I would run a narrower tire in front. It will look goofy if you have a fat tire in front and a stretched tire in back. I would probably do 225/35 for the fronts.