I finally installed evac on filter kit. Before evac top speed dropped to 108,110 mph with filter kit. Now today on ice with very little snow it shows 123!!!! Same conditions as before. It hauls hard to 100. Only other change is the 5/16 washer trick as found on this rocking site! Gas mileage 18, can`t see it changing. Also came across my first broken down RX1 in 2 winters and 4000 trail miles. That say`s alot for yammie dependability. Was going to buy an attac but the time is not right, and the RX1 is awesome!