I just switched from 225/50 rubber on the stock wheel to 225/45-17 on 17x8.5 wheels. The tires came with the wheels. After only one AutoX, the car is much more stable, turn in is improved, and traction is much easier to modulate in hard corners.
Stock wheels with 225/50-16:
5Zigen Pro Racer GN+ 17x8.5 with 225/45-17: