you shouldn't even waste your time mounting those 245/45/20's op. you either need to buy different rears, or buy different fronts. You don't want the front tires taller than the front. especially over an inch different. i would do 245/35/20's in the front with that setup. as far as front fitment, you can make a lot fit on this car. vorshlag runs 315's up front with a 20x12 rim. I run 295's up front on 20x10.5's.