Most have gotten lucky 4 STS with out a problem. Yes I do recommend replacing the bearings about every 2 gallons which stock ones cost less then $20 for both or do like I do and put ceramics in. I have even heard a lot about bearings and rods in high dollar engines like the OS V Spec failing so is it just STS low quality or could it be the power out put of a high performance engine? One thing for sure dollar for dollar a STS will out run anything in its price range.