yes don't use the washer. I made that mistake of using the washers and they kept coming loose and making noise. To be honest with you, I was not happy with ebay ones and they rust pretty quickly too (I live in the midwest).So I switched to Moogs and I am much happier. One thing with noises I discovered is that sometimes it is not the endlinks but the nuts holding the sway bar brackets the source of the problem if they are loose or not tightened properly.
FYI: I am lowered on eibach springs and I checked my sway bar...it is still horizontal even with moog's so no need for adjustable endlinks. If you are on corksport or anything lower your options seem to be the Ebay ones or the hardrace ones that are a little pricey. But you know what they say, you get what you pay for.
So try this:
1. Make sure you did not use the washers that came with the ebay endlinks.
2. Make sure the nuts holding the sway brackets and bushings are tight. As you know, they are hard to reach so it is easy to think they are tight while they actually not.
3. If you still get the noises, I would say try moogs or hardrace endlinks. I was almost at the point of buying hardrace when I realized the clunking wasn't because of the loose endlinks but because of a loose nut holding the sway bar bracket. After I tightened that noise was gone.
I want to emphasize that from my experience noises on newly installed sway bars on these 3rd gens are mostly due to an incorrect installation in one way or the other.