When I ran my 258 I started using the smaller filters because of the location over the motor mount. The motor mount got squishy over time and it pierced the PH25 while I was driving down the highway. After changing the motor mount the big filter got pierced again while I was bouncing on some rocks in the woods. We ran Amsoil VES full synthetic in our 2 stroke Polaris snowmobiles for years. When we told the Amsoil dealer about our results they didn't believe it and told us their product was still better than OEM.