On the under side of my '08 coupe just forward of the rear tie down on the left side is a bracket with a threaded stud that's not being used. I'd like to know what it's for.

The stud in question is at the bottom in this detail from the thumbnailed photo:

 

thats where you hang the JDM stuffed animals

 

I believe its for the track edition aero

 

THe photo is black and out of focus. Looks like an evil eye.

 

I thought it was pretty good figuring I was kneeling down next to the car with the camera between my feet. I only wanted to show the location of the stud, not the quality of machining on the threads.

The detail photo is black mainly because everything shown in it actually is black. Isn't that how cameras are supposed to work?

 

Ding , Ding Ding! Yup it's for the under body diffusers that come with the track model aero package. It has plastic diffusers around the muffler and the sides where this pic is taken from.

 

I like Barnabas's answer better.