onetrack: One also has to ponder the amount of stresses inside a pretty ordinary, automotive-based, L-4 design 2.0L engine, that's producing a constant 155HP, too.
I'd have to agree. Interestingly the original 1.7 L Theilert engine (which these are a direct derivative of) produced 135 HP but due to reliability issues was replaced with the 2.0 l engine producing 135 HP. One wonders how reliable the 2.0 L engine will be at the higher rating of 155 HP?
Unfortunately the only market where these will be attractive is one where there is no Avgas what so ever.