W211 2004, replace Avantgarde rear springs with Elegance?

[mbn]

I've never really liked the hard Avantgarde suspension. Now, one of my rear springs broke.
Can I use the opportunity to replace with softer Elegance springs?
If so, do I also have to replace shocks?

 

[OneForTheRoad]

Id say yes as the shocks are rated to the springs.