my car originally had a stealthram on it, but when i got it, the guy had swapped everything for a carb setup. Im really wanting EFI and would be willing to take the time to tune, or have it tuned. I dont have the wiring harness, just the PCM, 2 oxygen sensors still in the headers, and a knock sensor. Ive heard about vats, but since this is the original pcm would i still need vats tuned out?

Next what extra sensors will i need? Should I opt for a megasquirt system? And last, should i rummage through the junkyards for a wiring harness, or should i get one thats a bit more simple from painless? Thanks!!!