There you go that's what is most important.

IMHO and everybody has one, is that ABC engines were originally developed for high performance racing engines. But they also evolved into sport engine use because of the simplicity of break in. OS and Thunder Tiger came out with the ABN engines and they are even more simplistic and trouble free. They are new engine to the field and fly for most people.

The ringed engines have been around a long time and for some reason I prefer them. But they require more of a break in episode when new.

Be opportunistic and seek the best deal.