I really think the $49 for the aviastar is a steal. I think that the machining is excellent, the power is great, and the tuning is very good too, very similar to my Magnum XLS-46. I do wish I had my 4* done right now to see how well it will pull it around the sky, but by the 'feel' of the break-in on the bench, I think they are excellent engines and amazing values. OS engines be damned!
Curtis