I was really sceptical at first knowing that undercarriage is a huge drag on an aircraft. Then I remembered the Q2. It has its undercarriage in it's wingtips, much less drag. Just looked up the Q2 specs, not that far behind this aircraft. Given that the whole aircraft could be made from carbon fibre, I think that the weight could be lowered so much that a lightweight engine such as Rotax, may give close to the weight as is with this aircraft. I have not done an engineering study on this, I just using my mental arithmetic on general items. I do not believe the VNE though, the spars, even in carbon, would have to be strong and heavy. Why have such a high VNE, probably would not get there even in a dive.