The kartboy endlinks are good, yes. And they are cheaper. You can get the spacers from most retailers that you get the endlinks from, they look like really think aluminum washers. I personally would not recommend them though.
I originally bought the kartboy ones, but due to my own fault buying the wrong front sway bar I damaged the bushings on the front endlinks. When I bought the right swaybar I was on a time crunch and could not wait for replacement bushings so I had Whiteline endlinks rush delivered to me to replace them.
This allowed me to try both on my car, and I still have the kartboy on the rear. Those will be changed out soon, when I get around to buying the Whiteline rears. The kartboy are a solid buy and work fine, but due to the design, and the urethane bushings they use, they make an odd rubber sliding squeak noise any time you go over speed bumps or hit sudden dips in the road. It almost sounds like when you go to get into a car that has worn out struts. The Whiteline are slightly stiffer and are silent. The Whiteline endlinks are just a better designed product.