Originally posted by: Triumph
I think the original question was about changing the impedance of the speakers themselves. No, this does not happen. When you wire the two 4-ohms in parallel, the net effect that the amplifier sees is a 2 ohm load, which means more current being drawn. The impedance of the speakers is a characteristic of them - it doesn't change, only the voltage and current through them change.
Your speakers should be fine running in parallel, and it looks like your reciever can run 2 ohm loads, so I wouldn't worry. Wire those puppies in parallel on the single channel and you'll get 560w continuous at 2 ohms. That's alotta watts.