I recommend you to look up directly on Polk site with the part number, if they are timbre matched. Usually all Polk released a couple years apart, do sound similar with the same volume setting. If your receiver has a audio level setting mic, then they auto adjust individual channel levels to sound appropriate. If you are using these for surround application, you will hardly notice any difference. If you are using them as your main Front L, C & R speakers, there could be differences in the mid's and high's in the sense that they may sound a little muffled or not sharp enough, when you mix & match different speaker models.