Basically we have (2) speaker systems, or (4) speaker systems. 

Platinum - Kicker CSC Speakers and Diamond Audio Amplifier - Sounds Great - No compromises, just a great system
Ultra Platinum - upgraded Kicker KSC speaers, Upgraded Diamond Audio Amplifier - Gets Louder and Sounds Better. 
Extreme - (4) Kicker CSC Speakers and 4 Channel Diamond Audio Amplifier - more speakers = better sound 
Ultra Extreme - (4) Kicker KSC Speakers - upgraded 4 channel Diamond Audio Amplifier - GETS LOUDER and Sounds Better

4 Speakers is going to be louder and better at highway speeds, but 2 speakers is very good and we sell alot more 2 speaker systems than the 4 speaker systems. The 2 speakers can be upgraded to 4 speakers by adding an additional set of unplugged speakers, and using the original amplfiier to power all 4 speakers. 

In short
More speakers is usually better than more power
More power is better than less power
All of our systems are really good so no matter what system you choose it will sound great