Which ecm 06 ram 5.7????

I have a 2006 5.7 hemi out of a ram , do i need to stay with a 06 computer or is the 05 ok as well ? Can it be a 4x4 or do i want to go with a 2x4 ccomputer, is this going to matter? I want to get it running with stock computer with no flash for now ? Thanks ed