I still have my Sig Skybolt. It has seen a lot of flying. It is a builders kit but it goes together well. A 90 4 cycle will fly it fine, I flew mine on a 60 2 cycle with power to spare. The only issue with the Sig Skybolt is not to let it get too slow on landing, it will flat stall without warning. I have had to glue the landing gear mount back in a few times.