^^ try this first.

On the rear left hand lower control arm is a small sensor, when I had my OEM suspension put back in this wasn't put back into place and was making some noise when it moved, I would check this (would have seen it when you were looking at the rear end links).

Did you disconnect the end links to confirm if they were the cause of the noise?

Any chance that the noise it coming from the real parcel shelf?
I know from personal experience that it can give off a couple of unique noises (especially the clip covers).

If the design of the Whiteline HD Rear End Links hasn't changed, I would recommend not using them.
Had a bad experience where the design led to one of the end links failing and took a few small chunks out of the sway bar.

If you need something urgent, I have some Kart Boy end links that you can have.

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2015 Forester XT Premium
2020 VW Tiguan Allspace
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