This is a real pic of the E46 M3 rear damper.
I would expect we get the exact same damper
With the threaded body, what this damper lets you do is shorten the length.
This allows you to put preload on the rear spring so that when the suspension is at full unloaded travel, the spring still has some pressure on it.
That way the linear springs never flops around & chatters when it becomes unloaded.
I'm VERY happy to see this design.
