putting shocks in the background and you had to replace all of the suspension system over time which component for safety first applications do you do first?
It's tough to pinpont certain parts first to replace. The suspension is a "system"... not just individual components.
Typically with the LS... the rear left bottom spring tail bends or breaks. This is usually in the rust belt. This puts unusual loading on the left rear lower control arm... and it eventually starts squeaking. This may also wear out the rear toe links.
This starts a person down the road of rebuilding the rear suspension completely... including both upper and lower control arms... and shocks.
Sourcing replacement springs can be a challenge. Typically... springs can still be found at junkyards for a reasonable price... but the color coding and tags on the springs of the donor vehicle should match the the color coding and tags on the vehicle being repaired. Moog makes aftermarket springs for the LS... but I know nothing about the quality... or quality of ride they will give.
Shocks... are another story. Good shocks for the LS are hard to find... to keep or improve the quality of ride.
As said elsewhere here... the rebuilding of the rear suspension... may make the front of the LS feel "heavy"... and cause handling issues.
This leads to rebuilding the front suspension in the same manner as the rear.
Typically... the sway bars last longer... along with the steering rack.
I can't stress enough... don't buy cheap (inexpensive) parts. They do not last long... and will have to be replaced at sooner intervals than better made parts.