Polk center speaker question?

Barton82
Barton82 Posts: 20
edited February 2008 in Speakers
Ok i have the onkyo txnr 901 has 110 at 8ohms x7 . so i have polk rti4's for back m10's surround. and working on fronts, right now monitor 8t's....yeah long story, but I need help determining which center would be best/good for me with the receiver that i have? the Cs1,Cs2, csi3, csi5, ....I know the csi 5 is most expensive but will cs2 give me better sound with the 6.5's or are the csi 3's and cs1 just as good for my receiver? Any advice/direction would be great as i am still very new to home audio. I do know that i like POLK. thanks.