ok so there is 6 speakers in the car. 2 4" on the dash and 2 5 1\2 on doors. and 2 4" in rears. i am planning to put subs and change all of those speakers. 2 ways in dash and components on doors and 2 ways in rear and ima change the headunit. but. what can i do to amp the speakers? 4 channel den get a 2 channel one? or what please help. and i got a mono for the sub thats tooken care of. but for the speakrs i need help. thansk