The latest I heard was that a hydraulic Constant Speed Prop was required. I wonder if they'll extend the TBO after it acquires some service history. As it is, if you make an apples-to-apples comparison by assuming ~$10/hour in overhaul costs for the 800 hours you're losing, The cost compared to the rest of the rotax line is a staggering $46,667. I was hoping there would be a way to justify this engine on my plane, but it's looking bleak.