Yes, I have heard both many times. I used to own some Athena speakers and am very familiar with most of the Polks. I never did an A/B test or anything like that. But, it was quite obvious to me the CS2 was better. It should be given larger enclosure and larger drivers. Keep in mind too, that I really like the Polk sound. Some do and some don't like Polk. I am one that does. In fact, just bought a set of the Polk Monitor 30's that I am now using for my rears instead of the FXiA4's. Hence, the FXiA4's will be put up for sale. Just too tired to mess with it tonight. Maybe tomorrow evening I will snap a few pics and post them for sale. However, I am not sure how the CS2 will sound with the Athena towers. It may sound fine, but then again it may not. My guess is, the Athena center you have would work better. Have you thought about getting a second Athena center just like the one you have now? Maybe put a mono-block amp on them which would really make a difference. Not really sure, but it is a thought. You never know, that may work real good and be fully voiced-matched.
Cheers,
Phil