Over a ten year span , I have owned 5 YS engines; spanning from 91 to 140. I never had an issue with settings ( mixture or high speed) and all ran great on 20/20. As far as warranty , YS performance just warranted a new cam for my YS 120 FZ ( PURSUIT 120) that I bought in 2000 and have 300 + flights on . Now that's service !

In my experience with OS ( I currently have a 91 SurpassPump ( Kaos), 140RX ( BRIO), and 160 Fx( FOCUS 2 ) , they run well , but I doubt Hobby Services would honor a warranty 6 years later. A YS 160 will likely be my next pattern powerplant.

The bottom line is we should run whatever works for us.