I currently have a Sony STRDE635 HT receiver, 100w x 5, that powers six lower-end Polk speakers in a 5.1 setup. I'm thinking about upgrading the front speakers to something larger, maybe building Adire 281s, which are rated 150w I believe. Could my Sony receiver handle the larger speakers while still powering the subwoofer, or do I need to add a separate amp? Also, should I worry about new speakers timbre-matching the Polks? Any advice is appreciated, thanks.