After reading some post on using a separate amplifier for your speaker I have a few questions. I'm a novice in this. Most amplifiers I see are two channel. How do you use the amps on a 5 channel system? I do have a Hafler two channel Amp and thought of using it for my right and left front speakers. Does the Center channel speaker also require amplification? If I do decide to use separate amps for all my speakers and also decide to up grade my receiver should I buy a preamp instead or a receiver with less wattage since I won't be using the receiver's amplifier?