How's this original at all? In fact, it seems like something out of most sci-fi movies/space shooters around. If anything, it's ultra-unrealistic. i.e.: If you continue to hit your boosters, you stay at a uniform speed, but the moment you deactivate them, you slow down. And that's not even to mention the miraculous technology that allows you to hear sounds (explosions, laser beams) in the void of space.
Have you tried going to cruise mode and when you hit 300, kill your engines? I allways begin my attacks this way wich means that i go crashing in to my enemies at 300, blasting them to hell with every gun ive got . Kill your engines and control your ship with the thruster instead. Doing so will enable you of reaching speeds up to 200 without your thruster . Speed does decrease over time though.