You've got slightly wider tires than the car manufacturer intended. Using a 255 tire on an 8-inch wheel can put a bit more strain on the tire's sidewall compared to a narrower 245 tire. This might make the car feel a little less nimble in turns, as the tires might flex a bit more.
On the plus side, the wider tires should provide better grip when you accelerate or brake. Even though the tire's contact with the road isn't much wider, it's noticeably longer, which usually means better traction in a straight line.
