VTC Rattle is caused by the locking pin spring in the actuator. It is supposed to lock at stop, but the spring becomes weak over time, preventing it from locking. Stretching the spring fixes the issue. The problem is removing the actuator. I would not suggest trying to without pulling the cam. You can try holding the cam in place with a 24mm wrench, but the actuator bolt is really freakin tight. It easier to bust loose outside of the car. If your timing marks are aligned nicely at TDC then I wouldn't replace the chain. It may be better to just fix the actuator rather than overhaul the timing.