I run two NVX 6 ch dsp's they are $150 each I run two 4 ch amps and a two ch and two mono blocks amps for a 12 chs total..
4 ch for tweets a 4 ch for kicks and center ch and a 2 ch for door mids and two sub chs.
Simply replacing speakers as someone mentioned will not get you the surround clarity you are looking for I myself like to hear every last note and detail of the music..
It is like being center stage at a concert, you are on the right path bro keep us posted please...