it says 6 ohms (compatible with 8 ohm receivers) on the product spec page.

are there any problems/downfalls with using an 8 ohm receiver with these 6 ohm speakers?

I am purchasing the yamaha rx-v661
info found here:

http://www.crutchfield.com/S-F4DjsrtkNQE/cgi-bin/ProdView.asp?g=10420&I=022RXV661

-David