Daryle pretty much summed it up. You are now forced to buy a new engine every couple of years, and sport is getting very fractionalised with single engine classes, what I run in Florida I can not run in California. I have a Rotax this is now worth $0.00 If you own a Leopard it is worth $0.00 after this year but at least you had a couple of years notice. Thousands of motors are will or will be obsolete very soon. I do not think this is good for the sport. Will be running Rok and USPKS unless my driver goes to Europe to run KZ, which you can run any number of motors.