yeah there are no issues at all to change to synthetic oil at any time after the engine is broken in.... or to change back & forth. synthetic oil will not cause any type of mechanical failure. it could possibly allow oil to leak if there were bad gaskets since it is thinner, but thats very rare if the engine is sealed up properly.

thanks for the info on the TSB for 5/20, was just curious why you used it vs 5/30. i think 5th gen runners call for 5/20 & it is the same engine... but maybe there were some minor internal changes with the 06+ engines, i know they changed the head gaskets, maybe they made a clearance change too. but either way sounds like its accep[table to use if you dont have any oil lights come on & the oil analysis comes back good.