2015 Ford Focus ST
Maybe I'll look into these Ruthenium plugs. wouldnt hurt only having 70k kilometers on the thing to just put some new ones in and get the KAM reset, one less thing to worry about.People have mixed opinions on this. Your climate/ temp lows is a factor.
Personally, I slap one step colder in everything, lol. I have yet to see any proven issues with doing so.