Parabellum,
Early C18 were subject to quite a few failures. As they progresses, various mods were implemented culminating in the "Blue Ribbon" program later on. Since then, a few other improvements have been made especially with the wheels. In fact at this point you can use several stage wheels from the c20 series.
Like all c18 powered helicopters, close attention to TOT and overall temps will serve you well!
Rick