Hey - I'm currently going through this with my rear springs on '11 535xi m-sport with EDC... this has been an annoying process for me due to the lack of aftermarket options that retain OEM height.
The same side broke right at the bottom pad and was making weird noises. I actually ended up going with GetBMWPARTS to special order a spring set from Germany at about $144 a spring.
I bought both sides after researching and working with several BMW parts departments. The springs are specific to each vehicle and it's one of those things that requires them to do VIN lookup. I initially bought springs from a 550i RWD to put on but decided against it b/c I found out the donor was not m-sport (paid a cheap price for all 4).
What's interesting is some of the portals show a direct fit BMW spring but the department indicated another part that shows it doesn't fit.
Anyway I worked with GetBMWparts and got the following set with part number 33536786657 shipped out.
https://www.getbmwparts.com/oem-part...ng-33536786657
Now I'm dealing with damaged shipping - they showed up with deep scratches on the top part. they sent another set that showed up with even deeper scratches. I'll have to paint over I guess
I'm ultimately going to be changing these myself, curious to hear how the process went for you???