Just went to the local dealer to get some oil for a change in prep for summer...OUCH!! First found out that SeaDoo no longer makes (or provides) the XPS full synthetic. The replacement is now a synthetic blend that costs $20 a quart... un frekin unbelievable. $220 for two filters and 9 quarts of oil. I know the great debate but I do like full synthetic oil. I ended up buying the oil as I am not sure what a good replacement full synthetic oil would be for the 4-tec 4 stroke. Pitty is I only have 20 hours on the ski's since the last change but have only had them out every 6 weeks or so over the winter and the idea of old (time wise) oil just kills me and it will make me feel better to have fresh in them for the summer. Anyone have any ideas or know of a good synthetic oil for the GTI SE 155??????