The TBO in the UK of a Rotax 912S is 1500 hours and expected to rise to 2000 ish over the next 5 years. PFA aircraft can run engines on condition indefinitely, so this is of little relevance. A modern composite aircraft such as an MCR01 VLA with a 912 will burn 15lph at 140kn. My 180 Lyc burned 40lph of Avgas at £1.40, my Rotax uses Unleaded at 85p. Add in the difference in the cost of bits and the heavy oil use and frequent oil changes and it is what you would expect when comparing a 1940’s design with something 50 years newer. With 100,000 912’s flying worldwide and an exceptional safety record I would find it hard to go back having sampled the difference.
Rod1