I'm on a serious budget and I just purchased a Onkyo SR504 and Polk's RM6750 from amazon for pretty freaking cheap. Anyway, I found on craigslist a pair of Polk's R1 speakers for $20. It seems like a good deal, but will they fit with my new system or what. My room is about 20'x14'. I like how it sounds now, but i have two unused channels that i'm aching to use and since these R1's have a larger speaker, i'm thinking that they would be better suited as my front two channels. Am I correct?