Dynamic balancing is always a good idea to add to your engine build. From the factory Mazda allows up to 30 grams of imbalance. At Defined Autoworks we get this imbalance to 2 grams or less. Balancing is mandatory if the rotors and counterweights are not factory matched. This is also mandatory for engines being taken to over 7500 rpm. Price is for the service ONLY. Return shipping will be paid by the customer and TBD based on location. Once purchased please ship both of your rotors along with front and rear countweight to Defined Autoworks.