They came very fast. My 2015 Mustang Ecoboost has way is accelerating quicker. A way better idle. I didn't think I would notice any difference. They are way better than the stock coils. I did put Brisk plugs and changed out NGK iridium plugs . NGK plugs kept fouling out gapped .028. Plugs and coils change and my car is performing excellent. NGK plugs are not as great as everyone say. Brisk are great. Motorcraft products aren't great either. Upgrade with Accel coils and Brisk plugs. It makes a big difference.