GMC Acadia to G6 GTP cylinder head swap - need help!

Hey guys, I need some help from the resident experts! I'm trying to gather info on a potential cylinder head swap taking the GMC Acadia's higher-flowing cylinder heads and using them in a 2007 G6 GTP. They will be ported also. What I really need is info on the differences between the two engines, whether it is just the heads and gaskets I need to replace, or whether there are differences in valves/manifolds that will send the price of this swap skyrocketing more than it already is. I'm hoping I just need to put the new heads and gaskets in and the rest will be compatible, that is what the small amount of info I have been able to gather thus far is saying.

What I could really use is some sort of database of part numbers that I can look at to see if everything is the same. My dealer is pretty much useless for this. Does anyone know a good place to get this kind of info, or even can track it down themselves? I'm pretty sure this'll work, but I'm nervous to drop $1600 on heads if they aren't going to work.

Thanks for even reading, and thanks even more if you can help!