The RED Maintenance manual states a 1000 hour TBO. I know that it is certainly RED's intention to expand this based upon operational experience. Though it's still very early days for the engine, I can say that for the 40+ hours I flew it in a stretch, it was not necessary to add any oil at all! The engine does have and "avoid" RPM range for vibration, but it is not in the flight range, but rather the ground idle range. It was equally smooth in half engine mode, as it's a "straight six" developing power from one half, and the other half is still compressing, though not developing power.