Rob is just laying out a road map. A good one.
I spend a lot of time reading in the sub forum and now that you mention it I remember you getting a dud. Too bad. It's a great sub. If it works of course. I had to return a 505 that died about a week after I had it. Pretty rare for a 505. I bought it off amazon so the return was really easy and had the money back in my account just a few days later. Hope you have better luck in the future.
Personally I'd stick with the 600's since you like them a lot. If you get the CSiA6 you'll have a CC that will match some even better main speakers down the road when you decide to upgrade again. You WILL decide to upgrade again. You're sick like the rest of us.
I can understand the dilemma. Make it better now or even better later.
Quite a deal. I didn't get that code in my e-mail so I guess I've been bad. I also guess my buying a knife set from them a few days ago didn't qualify me. By the way, your link doesn't work for me.