Champions work fine in applications designed for them, and the occasional one calling for a copper plug that wasn't. Saturn S-Series seem to like a Champion better than the AC Delco replacement. Briggs will run fine one either NGK or Champion, Tecumseh's seem to prefer Champion. 90% of Chrysler products use Champions. Don't use them in GM(except for a couple of engines) or Ford. Anything Asian usually(but not always uses NGK(Kia tends to show up with Champion plugs) and if it's German usually it uses a Bosch plug(some VW's come with NGK). OEM replacement is always best.