Flyin' Miata sway bar end links (NB front, NB rear OR NC rear)
Product Review (submitted on November 20, 2016):
Having owned my Miata for 16 years, I've been through several sets of open, Heim-jointed end links. If the car is a daily driver, and you intend to keep the car for a long time, spend they few extra dollars on these with the sealed ends. You'll save money and NVH in the long run.
Compared with the price of the Racing Beat versions, this is a no brainer, pick this. With the adjustable center, it makes dialing in length a breeze with the end link still attached. I had the Racing Beat end links and they work without fail and haven't loosened over time. But if you play with the suspension a lot, adjusting them can get tiresome since you have to pull one end off to adjust the length. They can be shortened at the same length as the RB's as well.
My only nitpick is that the center is a round cylinder and a bit difficult to grip when tightenening the jam nuts. There are cuts at the end of the end for a wrench, but they're quite narrow. Most normal, thicker wrenches may not fit once the jam nut gets tightened down. My 6" ChannelLock "thin" crescent wrench was able to get in here no problem.