How important is the damping factor on amplifiers? What is a good rating? I am considering purchasing either a 5-channel amp or a 2-channel amp from ROTEL. I don't really need a 5-ch but thought it would be good for future upgradeability etc. I noticed that the 2-ch amps have a better damping factor however, and not wishing to compromise sound, am wondering whether the damping factor is important.