Hi, I have the following current system: AV receiver - STRDE875 (100W RMS in 8 ohms), Fronts: Sony SS-MF600H - 200W speakers, Center : Sony - SS-CN505 - 150W, Surround: Sony - SS-SR505H - 120W and Active Subwoofer: Sony - WM40 - 90W - 12 inch. All speakers are 8 ohms. I was looking to upgrade to...