The private pilot was flying the airplane and another pilot was acting as a safety pilot during the approach to landing. The flying pilot stated that he held the airplane in a left yaw during the final approach, and the safety pilot stated that he was looking through the airplane’s rear window at the airplane that was just behind them. The safety pilot said that he became concerned that the airplane behind them was flying too close and that he continued to watch as it overflew their position during the flare. When the safety pilot looked forward, he noticed that the airplane he was in was in a yaw condition, and the pilot had not aligned the airplane with the runway centerline for landing. The pilot attempted to correct the yaw during the flare, but the airplane landed in a side load condition on the left main landing gear and then veered off the left side of the runway. The safety pilot tried to take control of the airplane, but it continued into the ramp area and collided with two parked aircraft. The accident airplane sustained substantial damage to the left wing and the left side of the main cabin, and one of the parked airplanes sustained substantial damage to its rear cabin and tail section. The accident pilots reported no preimpact mechanical malfunctions or failures with the airframe or engine that would have precluded normal operation.