Amsoil SignatureSeries 5W20! You will be very happy with this oil I guarantee! I used Amsoils a lot in the past for my gasoline SM520 until 4-5 years ago, of several different viscosity grades from XL 5W20, series 2000 0W30, series 3000 HDD 5W30, 5W30, European formula 5W40. Among them, XL 5W20 and series 2000 0W30 were the best two oils at that time. (Series 3000 HDD 5W30 was a wonderful too, but series 2000 0W30 was more fuel-saving). I have not experienced Signature series 5W20, but is a much better oil than XL 5W20 which I was very satisfied with, so I recommend this oil to you for the fuel-saving and the quietness both!
