Hi David, good to hear from you!What brand/ model discs are they Martin and how were the old slotted discs?
Yes.. Exactly that David, one step colder than standard. You're 100% spot on here. Once the car is tuned, its recommended to upgrade the plugs to match, hence why I went for these. As you say, standard tune = standard plugs!Are they a colder spark plug? That's something recommended to do on the 2.0l EcoBoost if modding them- but as mine is running the standard tune I haven't bothered.