What makes a good stereo speaker?

For your sub stage I would look into RE Audio 12SX subs. These will hit hard and heavy. It will be hard to find a sub that will match them in their price range, that does not require this amount of room. The 12SX only required about 1.5 cu ft of space, sealed, ported your looking at 2.0 plus cu ft of space. If you want 2 of them get the D4 model of this line, wire them to a 1 OHM load, to a 1 OHM stable amp that will give you at least 2000 watts rms, as each sub will take 1000 watts rms. They can and will take more than the listed 1000 watts rms. I am giving my wife's RE Audio 12SXD2 1500 watts rms. Everyday all day.