3900 into a 2005 G6GT (3500 non vvt)

[Noodles]

The engine is going bad in the g6 I am buying and I can get a 3900 from a 2007 montana, just as cheap as I can a replacement 3500. Can this be done, and if so, what does it entail. Sorry if I missed this with the search feature, but I couldn't find anything.

[caffeine]

I'm pretty sure it's been done before but I have no idea how involved it is. At the very least you'd need the engine harness, ecu, and maybe trans