As Nuke stated putting 8 ohm impedance speakers on a system optimized for 4 ohms won't hurt anything although it may change the amplifier's response curve slightly.

And you won't hear the difference. Unless you are one the "golden ear" crowd who can hear a mouse break wind at 50 yards. <img src="/forums/images/graemlins/rolleyes.gif" alt="" /> <img src="/forums/images/graemlins/drunk.gif" alt="" />

1998 Sportage - Gone.
2004 Honda Civic Coupe.
2007 Suzuki Grand Vitara - She got it.