IIRC you can use the same transmission you just have to get a bellhousing that fits (manual) auto you have to get a new transmission i believe. ECU is a deffinate no, it would need to be replaced. the wiring harness would need to be one for a V8, the kmember is different
depending on the springs you would more than likely need those as well, not to mention all the engine accesories ofc (altenator, power steering, A/C etc.)
Redfire '04 V6 - K&N CAI, Divorced duals, Bama Tune, EGR Delete, Gauge cluster LED overhaul.