So the first thing that comes in mind in general is if the springs have been installed correctly, refer to this install video of the Eibach springs and specifically regarding the bump stops @ 3:31, which i believe might probably be behind the noise you get
Just the springs.Ok... yours came with anything else beside the springs? In my box only came the 4 springs... just checking if need other part to install them
I will verify with a friend of mine that it may need like a rubber spacer between the arrows of the thinner side of the springI just got mine put on and there is a squeak at the rear when going over speed bumps. They were installed by someone very experienced with installing springs on BMWs - said it was practically the same procedure as an F8X - so I trust they were done correctly. Hope it goes away over time.