In my first Monte ('72) I did stock upper lower control arms with a full P-S-T Polygraphite rebuild. That was in the late 90's early 2000's. Kept the springs and updated the shocks. Rode and turned like new. Friend did the work on the weekend for a $100 bucks and case of beer. Kept the car for about year after the upgrade and did not have any squeaking.
In my current '70, just went with tubular upper & lower with coil overs. Haven't worked out the bugs yet, but am impressed with ride and handling. Since I replaced everything, I didn't have to have bushings pressed in/out. Did it myself without a lift in a little over 3 days (4 days if you include the fuel sending unit swap). Have to get the rear updated next. It's a never ending flow of $$... LOL!
So I'm with the others, keep the springs if they are working for you and update the rest.