What are the most innovative gravel bike handlebar extensions for achieving aero positions, considering factors such as comfort, adjustability, and aerodynamic gains? Are there any game-changing designs or materials that have recently been introduced to the market, and how do they compare to traditional options? How do these extensions interact with the riders body position, and what are the key considerations for optimizing aero performance while maintaining comfort and control? Are there any specific extensions that excel in certain conditions, such as rough terrain or high-speed descents? What are the trade-offs between aero gains and weight, and how do these extensions impact the overall handling and responsiveness of the bike?