[Receiver & Speaker question?]

I own a pioneer 6x100 watt receiver and the salesman at the Goodguys told me that if I bought the RF-7's or the rf-5's that I would most probably burn my receiver out and I would destroy it. He said that I would be wasting my money on buying the RF-7's or RF-5's because my receiver wouldn't be able to allow the speakers to work probably and that I would lose performance. He told me that my best bet was to buy the RF-35's. Is he right? I need help thanks.

[RF-35 vs. RF-5]

Which one is a better buy? The only difference I can see between the two speakers is that one has a 6 inch tweeter and the other has a 8 inch tweeter. Is there a big difference between the two in performance and would I be able to tell?

[Rear speakers]

I am using the RF-7's as the mains.

[Rear speakers]

Can you use the RF-5 or the rf-35 as your rear speakers in your home theater system? Would this be a good idea or should I just buy the surround speakers instead?