I contacted GNS about their engines almost a year ago, Once he found out I was considering it for an airplane he hung up. I called him back and he explained he wants nothing to do with airplanes, doesn't want the liability. He is a pilot himself. He clammed up about even talking about it once he knew it was for a plane. Too bad, he has a lot of knowledge about the Yamaha engines and would be a good resource. Yes, he pumps those Yamaha motors up to some incredible HP for sure.