I have replaced the front shocks on my 2011 S40.
Here is what I put in:
Front right shock absorber
https://www.autodoc.co.uk/kyb/826847
Front left shock absorber
https://www.autodoc.co.uk/kyb/826848
Front shock dust covers
https://www.autodoc.co.uk/kyb/828155
Front struts (buy two of these)
https://www.autodoc.co.uk/kyb/828367
If you choose to buy these items, first contact the seller to make sure they fit your car. I do not want to advertise autodoc, it is simply the place where I bought my items.
Also, don't buy this stuff second hand. Good aftermarket parts are the way to go.
I did not replace the springs, not sure what you need for that job.