Just installed eibach springs to my s2000. Clicking noise from the rear whenever i hit a bump. Any ideas what this is from?

 

mine clicked from the front when I forgot to put the rubber gasket between the spring and the bottom perch of the strut. It's easy to miss if it sticks to you stock springs when you remove it and don't notice. Check your stock springs to see if it is stuck on there or check your struts to see that it is there.