We're not negative about the checkers they do serve a purpose but it's just not the same as a true dyno.I use a MM motor master myself to keep track of my motors at the track it is small and convenient and serve's it's purpose,but I tune my motors on a turbo dyno,it's much more sensitive to small changes such as springs and brushes,as long as you have a base reading on your checker you should be alright.I have seen some fast guys use motor checkers to tune with,so it's all good as long as you know you're readings