Rumour is there are to be no more tuning kits, and the new
JCW model will be a factory installed option only. Of course its all rumours at the moment, the new
JCW model hasn't been officially announced, and I wouldn't get excited about ordering it until it has been.
The factory
JCW is likely to have slightly more power and better brakes. I think it will be like adding the tuning kit again to the stage 1, so not really that much of an increase, and I bet it will cost more than doing that.
I'd be tempted to wait if you don't want/need to change cars now, I needed to change a year ago so I purchased the S and then found myself upgrading to the Works kit later on....