I will not recommend any particular speaker but I will try to help you decide the best route. I too am a car nut, and so an analogy along these lines may be in order. As you know, some people drive a car to get from point A to point B, and that is the extent of their relationship with their car. Others, like you and me, take pride in our cars and just any old car will not do. We want something that is going to look good and provide a level of performance that exceeds most peoples expectations or needs. Good speakers are like a good short block, it is the heart of the system and if you skimp here, you will only pay for it later as you add horsepower. Same with audio, if you skimp on the speakers, no amount or quality of amps, receivers, or other audio components you add to the equation is going to improve the limits of the speakers.

I suggest getting three speakers of higher quality (usually means more money) and then you can add on to that, as your budget allows. You will still get awesome performance with three or five good speakers, compared to the speakers you own now and you will be happier in the long run. If you get the bug, I am sure your budget will expand and you will not have to start over. You can always use your Bose for rear surrounds until you can afford to upgrade later and you feel it adds to the experience.

Just like a car, once you have a good short block, you can add whatever heads, cams, manifold, turbo, supercharger, or exhaust to make it perform even better without blowing the engine.

Hope this helps.