If it were me, I'd check for vacuum leaks first, gasket leaks second, and IAC third.

I'd rule out each of those as possibilities, before making any changes/updates/upgrades.

Then when you've fully resolved the idle situation; revisit your same question... To carb, or not to carb...

Either way (carb of EFI), you can ditch the charcoal canister / smog pump gimmicks. And IIRC you can do an EGR delete for fairly inexpensive.