Possible coil bind?
 

So i've jacked the car up today to diagnose a strange metallic sound i hear from time to time (it sometime sounded like the exhaust was banging about), we were not able to find anything however we did notice something strange on the rear springs, it looks like the bottom coils have come together as they also have marks in them, is this what coil bind looks like? The car has Eibach lowering springs on stock shocks. If it is coil bind does this mean the springs can break under hard cornering? What can I do to fix this?

Picture attached.

Normal, and It's what they are designed to do. Eibachs are progressive, so they get stiffer as they compress. They do this using the pitch between coils and reducing active coil count when they compress. That isolator sleeve on the spring protects the coils from rubbing through the next coil's paint.

The sound you're hearing could just be it shifting on it's perch as it's loaded/unloaded.

I did not touch the coils to get a feel for them, but the two different looking coils are covered in some kind of rubber and they're supposed to touch, am i understanding this correctly?

Yes