$1900 for a used black Scar is a good deal as long as it isn't beat to death. Advantage Scar - they have long barrel and bolt life.
"Upgrades" I tried and didn't end up keeping ...
Different bolt handle;
Different safety levers;
Handle Defense lower (Scar-17);
Troy Micro sights.
I like my Scars to be bone stock save for ...
Optic (ACOG usually)
Geissele Super Scar Trigger
If I wanted to spend money on something else ...
Metal stock latch
They're pretty squared away for my uses. I have no interest in rail delete kits, extended rails, non-recip charging handles, ambi charging handles, that hideous Vltor stock, etc.