Gene, that is an excellent deal!
I purchased my SKSHT500 set from circuit city after
Thanksgiving in 2002 for $199.
Perhaps it is because the next model came out, the 510?
I will also look into my speakers and test either tin foil or go have a sheet of metal cut to be placed under the center channel.
However, I have had problems with the front speakers as well.
I asked Onkyo regarding how many people have called in for the warranty due to interference... they claimed that I was the first customer.

I laughed at them on the phone... and asked, "are you kidding me?"
Gene, let us know how it goes!
Thanks,
Dave