That is what I did , I had 4xRF -3`s they where great speakers , but I wanted more bass & tamer high`s , so I gambled & got a set of KG 5.5`s they where cheaper then going for the RF-7`s , It was defiantly an upgrade -man can they putout some bass , the mids & highs are excellent also -not bright like the 3`s where , I was final able to buy 2 more + a KV-4 for the center ,now I`m in audio/video nirvana , it`s one of the best things I did for my system getting the KG 5.5`s , there is one thing you will need to check though - this only happened to one of my 5.5`s ,but the glue failed & the back panel came lose on one of the KG`s so I had to re-glue it ,not a big deal .but you will want check & thus far non of my other 3 KG`s has this problem so other then that one problem they have been perfect in every respect for music & movies , If you can get them for $400 or less IMO they are well worth it .