Many Oggy Knobbs kits are designed to fit without any fairing modifications, also known as "no cut", whereas many other brands require cutting into the fairing.
Some applications may have both a “cut” and a “no cut” option. The “cut” application will be a less expensive and lighter option. "Cut" applications are particularly suited to use in racing. "No cut" applications are more suited to road use.
Please refer to the fitting instructions for your particular model to view the modifications required to fit a “cut” type of kit.