I have a 2004 pt cruiser and the motor slung a rod and I'm going to replace everything the motor, trans, the fire wall computer and the computer on the ignition switch and keys its self

It's possible but I don't think there's a safe way to answer this, as there were several small changes made throughout the model years with the PT cruiser, specifically the power distribution center is different from 2006 on up, both use NGC (next generation controller) which is good. You'll have to pay attention to which sensors you keep from the 04 and which you import from the 08, along with the variations in the wiring harness, if you are picking up an 08 from someone or a parts car, get all of it you, don't forget the computer still needs programming for VIN.

But as long as the plug's that plug into the fire wallare the same it should work right

If I change all three computers how could it bere programmed on the vin