If your amp is designed for an 8 ohm load, you might be better off using 8 ohm speakers. It isn't usually a problem if impedance rises, but power transfer might be reduced a little bit. Impedance at low frequencies is sometimes more of a problem.Glad you're enjoying the speakers you won in the 25,000th post game. Colin Hester made the donation of the albums; I just agreed to substitute them for speakers if the winner had the albums or didn't have a turntable or whatever. So thanks go to Colin in this case.
By the way, what resistor are you refering to? Do you use a damping resistor or some sort of level matching?