During the past weekend I semi-successfully installed the 22mm Whiteline Rear Sway Bar with Kartboy Rear End Links on my 2011 WRX hatchback. It's successful because most things went in smoothly --- didn't have too much trouble with most of the bolts, and most importantly, I'd like to report that the End Links fit perfectly with the WL sway bar. No extreme angle at all. I've learned that some people experienced the weird angle problem with this combination, so I guess they must have changed something to fit better. Just wanted to let you know.
And the "semi-" part, is that I just couldn't take of the inward lower control arm bolts. My impact wrench didn't move the things at all, even though I've sprayed PB Blaster multiple times over a period of 3 days. So I gave up on the supporting brace. It should be okay without the braces, right?
Now the car feels very stable and tight during corners, and there's no NVH increase at all. No noises, squeaks or bumps of any kind. So far so good! It's definitely a very noticeable improvement over the stock rear sway bar.