I have had good luck with the coils. I had an intermittent spark on the racer once. It has a twin coil system. I went to change both coils, but found a loose connector. I had changed one coil, but did not change the other when I found the faulty connector. The other coil has run for 11 years. The one I traded out has run for 9 years. They were not very expensive at the time. I bought extras, but have not used them, except for the one mentioned above.
David