2004 Toyota Corolla Toyota Corolla S

I bought my car from a Toyota Dealership used, after it had 8,000 miles. I use 5W30 oil and regular gasoline (87 octane). When I first started using the car, the acceleration and braking were very sensitive, it felt like I was driving a sports car. After a couple of thousand miles, the acceleration and braking lost their sensitivity. I have tried an oil change with synthetic oil and tried using higher performance gasoline (92 or 93 octane) but neither brought my lost sensitivity back. I bought a K&N air filter after I lost my great acceleration. My acceleration is good and the brakes work well, like a family car but I want to bring back the acceleration and braking I had so I can make my car feel like a sports car. How can I bring back the lost sensitivity?