I will be switching to synthetic oil but I would like an opinion as to when, based on how long it takes for the Ecotec engine wear particles to get filtered and changed out. I am going to have the dealer change the oil and rotate tires at 15000 mi., and by then IMO the majority of particles would be worked out. I intend to do 10,000 mile oil changes with synthetic. Sound like a good plan? Anyone here done oil analysis? :-\