I got the HK 8000 from one call. Now I need a 2 channel amp to go with it for full on 7.1 surround sound. I was leaning to either a HK 2000 or 4000. With the 4000, I would use it to passive biamp my mains, but it I were to go with the 2000, would it be best to use it to power the mains or the rears? It is rated at 100 watts per channel, while the 8000 is rated at I think 110 watts per channel. Bottom line, would the 8000 reciever's built in internal amps be stronger than the 2000's or not? Thanks in advance.