What other speakers are you using to go with the center? If they are all Cerwins and this center is the one that matches them you are probably better off keeping the cerwin, at least untill you upgrade your speakers, that is if you upgrade. Something you may want to note is that the Yamaha says not to use 4 Ohm speakers. Cerwins are generally pretty efficient, so you most likely won't have a problem, but someone who knows more about impedence and what loads this receiver can handle would be the one to answer this for you. Another thing to note, I don't think you should get hung up on using bananna plugs for the center. They do not provide a better connection than bare wire, they only make it easier and faster to hook up, unhook, the speakers if you have to move them around. If it were me I'd just use bare wire as no work modifying the speaker would be needed, especially considering the fact that there will be no difference in the sound quality if you use banannas or not. Conversely if the Banannas you use give a bad connection due to defect in manufacture or being incorrectly installed, you can get worse sound. That said you can go to radioshack, or look on parts express's website (I can't give you a link because partsexpress is on the outs with audioholics {for good reason} or I'd try to point you in the right direction) or just do a google search for speaker binding posts for that matter. Just be sure that the posts will fit. To reiterate my suggestion is to go bare wire, cheaper, faster, no loss in sound, no fear of damaging your speaker.
