1) Currently have Koni Sport/H&R Sport and stock sway bars.
I'm leaning towards the Perrin 25mm F&R, unless I hear a good reason to go with the 22/25
2) One of my questions is in regards to the stock endlinks. Many drivers have complained about the stock being week and having a high failure rate when tracked, however does that apply to the 2011 WRX? I'm hearing mixed reviews on the stock endlinks, those that have nothing to gain and those that sell after market. One installer I know says that the stock endlinks on the 2011 WRX are indestructable. Some say that the stock are a weak link, especially sellers. Looking at the stock bushing/bearing/ball socket on the stock endlink I would say they look pretty damn tough to me.
Test them out, if they break they break and gives you a reason to upgrade. Of course that means getting under your car again. If you have the money and want to change them, go for it, just dont ditch the stockers in case you break the after market ones.