Well I got Saito 72 with OS F, OS 15 LA and OS FP 40 and they have been great engines. Most people blame their engine while infact they might have had improper run in.

BUT Tower 46 is a hell , I put that on a friends trainer, it didn't actually like to flame out but it's leaking on the first day I got it.
Now I might have a bad engine but surely I'm not gonna ever get another tower, besides 4 stroke is too cool too pass.