Had it checked out.....now have a price.
Springs are dealer only $150 each - recommend you do both side.
Labor is 2.5 hours @ $72.50 local
About $480 before tax.
I was shown the spring and were it was cracked...in fact the small piece that was rattling was removed....the spring is still there fine but recommended that I fix it as soon as possible.
You can see the spring from the rear when the car is up...look above the suspension near the wheels. Mine was rusted