I am not 100%, but as far as I know you can use ute springs in a sedan just like a ute can use sedan springs. They are different however.
As for lowered shocks, it really depends on how much you are lowering it. If it is a minimal amount then stock shocks will be fine, if your going to like ssl etc then may want to look into some lowered shocks. I picked up some rear KYBs for like $80 ea on ebay.