I'm going to step off the beaten path with this one. You're starting baseline is 30%. Okay, great. You're looking at 45 to 50cc engines, but have started to move toward a 58. Again, great. Now the side step. Why not compare some weights and prices and consider a Cunningham converted G-62? Weight is inline with the 58. Power is probably equal to or better. Reliability is a lifetime given. I have no idea where Evo will be tomorrow. Price is comparable. Ignition warranty is lifetime with RCIGN. Later uses is higher with the 62. Availability is likely sooner with the 62. Getting full and easy access customer support is a high priority with the 62, not that yoy will need any.

My choice at 30% would go to the Cunningham G-62. It's quite a bit more powerful than the DA50, (quiet, DA owners) with no known reliability issues. The base engine has been in production for decades, making parts availibilty a non issue.

Pat