reducing mass frees-up a pony or 2 for acceleration. lighter rims, maybe a lightweight crank pulley, if you are always near home and help is easy to get - leave the spare and jack at home. Don't haul around any excess gear. If you literally never have passengers, take the seats out.
you can make the car more fun to throw around the corners, cops rarely care how fast you take a legal turn. stiffer springs, fresh struts, maybe stiffer rear sway bar and stickier tires, good brakes, etc.
9-11 pounds weight = about 1hp, 4 pounds rotating mass = about 1hp.