This is a real wild guess but I'm thinking an '03 just has to meet '03 emissions so if you pick an '03 or newer V8 from a "passenger" vehicle, not a light truck, and retain ALL the stock parts, computers, cats, etc..... when done if that V8 still conforms to the original emissions requirements, you should be OK.... at least in BC, Canada that works.Good information! I've currently got an 03 SE w/ 2.4L Auto. 4" Short arm, 33x12.50s. Down here in South Mississippi I was looking into a magnum swap if that state allows swaps with their emissions. So if anyone is from there and can shed some light on what other stupid laws they have up there that would be great.