I have recommended anything else, zero times. I am not a fan of Delrin on vertical links.
NVH will not be an issue. I have about 1000 sets of these out there and can count on less than 5 fingers how many NVH issues I have dealt with, with these particular pieces. They really are the bees knees. ;)
When putting my poly vertical links on...I finally realized the benefits of a spherical bearing. The load on the vert link is not purely "vertical" (along the axis of the link), there are significant traversal forces and movement. In the case of poly (and delrin), it will load the bearing asymmetrically to some degree, at weird angles. I'm not sure if this is the correct way to explain it, but when you see the mechanism at different height, you will notice that the vertical link joints (in this case, the bearing) actually require some freedom of movement. A solid ball/socket type of joint seems to make a lot of sense in this application, which I think is reason why Kelly is so adamant about the TCA045's.
I'm sure a lot of my terminology above is wrong, but well, it's sort of hard to explain. After I realized how the mechanism works, I wish I would have gotten the 45's.
