From my understanding, you would need the engine, harness, and a NEW PCM. Having not put a PCM in a crossfire yet, I am not sure if they come to us like others do as "generic" no programing in them at all, or "specific" just need to program VIN and SKIM / key. Worse case scenario you would need an immobilizer also, so you could program whatever srt vin/skim into the two modules so the theft wouldn't keep it from running. Th trans is not a problem, you can use whichever, the NEW PCM doesn't care, it just learns an auto trans, when it sees the signal.