The stock ignition module is also made by thunderheart. I'm guessing what you are referring to as the thunderheart is the adjustable ignition. A lot of opinions on this. Some guys say they felt a big difference. Others guys say they don't. IMHO, it doesn't seem to make much of a difference in performance, but it makes the motor smoother. I noticed that immediately. I also noticed that I had to turn my idle down after installing it, so it must have more initial timing than the stock ignition. Overall, I'd say it's a good investment. I would probably install one if I bought another big dog.