system for my car.

and how are the pioneer subs?
 
for the door speakers. what amp will i need? i need the cheapest possible that still will make it sound good. and what about for the sub? i will more than likely get the sub at a later date but i want the door speakers first and foremost.
 
what about for 4?
 
suffice as in it wont take the speakers to their max potential?
 
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