If you're really that hard on wheels I'd go for 15"'s and a nice set of 205/50x15 or even 225/45x15. Convert to 4x100 and you'll be tripping over options. Stay on 4x108 and someone just posted up a set of 15x7 or 8 on this site today. I don't think that you need stronger wheels as much as you need more sidewall. Motorsport wheels are really strong but you'll never find a prepared rally car tackling anything short of a 100% asphalt stage with 40-series tires.