I have H&R's/Illuminas in my car. When there is a person(s) in the back seat my car makes a loud clanking noise when I hit any little bump. When there's nobody in the back it only does it when I hit a really big pothole/bump. What can this sound be? A theory is that the springs are compressing really fast and the coils are hitting each other. Any Ideas?

 

are you sure its not the exhaust hitting the axle or body? thats a pretty common issue with anything other than stock. if it is the coils, you can wrap them with split loom or similar.