05 wrx - better milage oil and plugs

Thanks, Ed! Similar results here...

As to "hotter" plugs for the OP: the heat range of a plug is designed to burn hot enough to keep it clean (from fouling) without getting so hot as to cause pinging or pre-ignition. With computerized fuel management, there's seldom a need to change from the mfr's recommended heat range unless you're REALLY off the chart with your driving style (long hours at way above normal speeds, similar long hours sitting idling in cold temperature traffic, those kinds of things) or you've got a SICK engine you're trying to limp along a little further (for example, we used to put "hotter" plugs in oil burners....) Stick w/ what the book calls for and you should do fine.

Rick

Rick