Honestly I couldn't tell you since I have never heard of KEM tuning... but I know that Bill is considered one of the best in the business, if not the best. look up their "about us" page to see more on who he has tuned for. IMO he is the best because of his care for his customers when they are in trouble, and his desire for safety and longevity of the engines. He can tune an engine to make a ton of power, but he wants safe power, not just a lot of it. I hope that helps
