Bookshelf are nice if that's what the room and budget will fit. I have rb61ii as back speakers and I have owned many reference line floor standers including rf82. The rf82 will give you a much better front stage than the rb61. Sub or no sub it's night and day. Even crossed over at 80hz the rf82 will give you a bigger more effortless sound. Still a lot of bass above 80hz and the rf82 will outperform the much smaller rb61. My advise is the rf62ii and rc62ii.