Karboy endlinks are solid aluminum with "custom made aerospace quality" polyurethane bushings. The endlinks attach swaybars to the lateral links and control arms, and act on the bars as you corner. By installing these much stiffer links, I think I increased handling responsiveness.

Ooooh pretty:

figure 1

The cost was $180 for all four plus $3 shipping and tax. As a bonus, they come with an atomic fireball and stickers (see figure 1).

These are the links for a GC/GG, the key difference being the front lower bushings which have a smaller hole. The install was pretty straight-forward- take the old ones out and put new ones on. The rear would have been a lot easier with ramps because you should do it with the car under the ground. I had a fun time crawling under there. To prevent knocking they come greased, but if there isn't much you should throw on a bit more. I asked Tom what to use and he said anything would be fine and that they use sythetic. The bolts should be torqued to 30 lb-ft, and you need to make sure the washer is on the outside of the bushing so the bolt doesn't pull it out.

One issue I have heard of is contact with the lateral link with an adjustable bar set on full soft. The fix is to not be a sissy and use a stiffer setting. This is because the KB rear links are a bit shorter than stock. When he was designing them, he found the stock links hit the fuel filler tube on a lowered car. It hasn't caused any problems for me with a 18mm turbo bar.

I also purchase a set of front and rear urethane swaybar bushings. These go along with the endlinks to reduce compliance, and were something like $12 a set.

Here they are installed. Front:

It takes a wrench and all of five minutes to change the bushings:

Bushing and rear endlink installed.

As for driving feel, there is definitely a noticable difference. They take out the compliance of the stock links, so turn in is quicker and more precise since the swaybar loads pretty much immediately. The turn wheel, car starts to turn in-> swaybar loads-> car settles into corner delay is gone. I've been on a few drives, including a long one out to Mulholland recently and I'm pretty happy with this stuff.