While it is possible to modify a Harley Davidson Sportster to enhance its performance and make it resemble a sports bike to some extent, it is important to note that the Sportster is originally designed as a cruiser motorcycle. It has a different frame, weight distribution, and other characteristics compared to dedicated sports bikes.
Modifying a Sportster to be a full-fledged sports bike may be challenging and may require significant modifications, including changes to the frame, suspension, engine, and other components. It would likely involve significant time, effort, and expertise.
These modifications could include upgrading the suspension, brakes, exhaust system, and tires, as well as adjusting the handlebars and foot controls for a sportier riding position. While these changes can enhance the Sportster's performance, it may still not match the performance of a purpose-built sports bike.
If you are looking for a motorcycle that is specifically designed for sports performance, you may want to consider other models or brands that are built from the ground up with sporty characteristics in mind.