315/35/20 on 20*12 wheels

I'm sure the wheel to fender issue has been discussed to death. Having said that does anyone know how to keep the 315/35 from rubbing with a 12 inch wide wheel?! I bought the Charger with Savini wheels on it already. I didn't corner hard before it needed rears so I bought same size; 315/35/20 but this time with Michelin Pilot 4S. Any hard cornering and it rubs like crazy...I'm afraid to take freeway offramps! It's already at the edge of the fender lip so a 25 mm spacer would have it sticking out 70's muscle car style and grind the outer fender instead. Will a 10 mm spacer be enough to push the wheel out but not rub outer fender? 305 tires not narrow enough to bother? Bite the bullet and get smaller wheelset?