Another is it diff bushings
 

Leaking diff bushings?

Doesn't seem like much fluid there. But if the stock bushing is still there, then that's probably the culprit. I would check on the subframe member and see if you can identify the source of the fluid - if from the bushing, it will drip down the subframe member also.

There is a diff breather tube, but I thought it was on the RH side of the diff and wouldn't think that pattern of leaking fluid could be from it.

After watching the beginning of this Youtube video it appears it's the start of the deterioration of the center bushing.
https://youtu.be/PZZA1bGpa9I

The center bushing is the only one with fluid. None of the other diff bushings are fluid-filled.

It can leak slightly (as appears to be the case here) or it can explode (like mine did).

Thanks, I'll break the bad news to my buddy.

If the diff puks fluid it will come down right at the spring bucket toe adjustment on the left side. Those tears of shame are
coming from the diff bushing.

The diff bushing has 2 chambers of silicone in it. From the looks of the picture. Only 1 chamber ruptured. Jar did both.

The diff breather is on the right side of the diff cover. The hose runs to the left, and stops inside of the sub-frame on the left center.

What I have found is that all of the silicone filled bushings on the Z has 2 chambers of silicone. The silicone bushings on the Z are, the front lower rear control arm bushings, The diff bushing, the front bushings on the rear sub-frame.

In the pic. You can see the diff breather hose. It's the little black hose, not the stainless hose.

Have you driven your car with the new subframe bushings yet?

No, it's still sitting on jack stands. I'm working on the front splitter. With just the SPL diff bushings. I couldn't really tell the difference with noise and vibes.

I saw this post and thought I'd check mine...looks like the tears on my face right now...