Would you mind posting up a pic of the OEM link next to your DIY adjustable link for comparison? The first question that popped into my mind when I saw this was what materials are the parts you've put together made from, and how does the adjustable endlink compare to the OEM link in terms of thickness, etc.
Sorry for the delay on the picture detailing the comparison between the OEM endlink and these. As you can see, the custom DIY endlink is just a hair larger in diameter; however, without the stress from preloading the sway bar, these endlinks have held up remarkably well thus far. All four ball joints are in amazing shape and still sealed. I have noticed that the first couple of FSB movements in the morning, the ball joints have created a few "popping" noises. However, after 50-100 feet of driving, the joints lubricate themselves and all is quiet until the next extended period of non-driving.
As for the handling, I can't say I've noticed a significant improvement over the stock links...most likely due to the lack of a corner balance alignment. Steering feel and comfort are the two most noticeable differences since installing these. Steering is a little more responsive and predictable...basically, the minute you move the wheel one direction or another the car responds right away. Second, with the preload removed from from the front sway bar, the coilovers actually seem to provide a significantly "smoother" ride.
I'll give another "durability" update hopefully in 6 months should all be going as planned. If something fails beforehand, I'll be sure to update this thread as well. However, after roughly a month and 2k miles (travels to H2O), these links seem to be everything you'd expect from them. :thumbsup: