That looks way better/more realistic stabilized than it does without.
They blur is from in-camera motion blur. You got rid of the motion (shake) but the blur is still there.
If you're going to be on an empty road when you shoot for real anyway, why not just drive fast? How fast are you trying to feel anyway?
Fast cuts and clever angles accompanied with loud engine noises and tires squaling will feel faster than a false speed shot.
Get the camera low to the ground on the car so you see a lot of pavement go by fast. The lower it is the faster it will feel. Turn the camera sideways looking out a window instead of straight on. The scenery flying by fast (if it's close to the car) will be much more noticeable than a ditant landscape slowly moving by. Finally, shoot tight shots of your car and driver, pan the camera the opposite direction the car is moving. It'll feel faster.