Originally Posted by SamboTT@ByDesign

At 20,000 miles it becomes much more realistic as a preventative maintenance. If the car is upgraded I would do it for sure at 20. As for the coils I have been monitoring and changing them periodically they seem to be quite robust and it’s not necessary unless they fail. They are basically good until they’re not as in an isolated part failure which does happen but much better than the previous generation cars. At the same time they are pretty inexpensive so it’s not about peace of mind.