E38 or E67 swap into 2006 Grand Prix GT supercharged

So, as the title suggests I am exploring the possibilities of swapping either an E67 ECM or E38 ECM plus the matching TCM into my 2006 Grand Prix GT L32 3800. The primary purpose of the swap would be to have the full flex fuel capabilities without having to change between tunes manually. Aside from the licensing requirements and re-pinning of connectors and whatnot I am not seeing any major obstacles as both ECMs were used in this year of W-body. I was just curious as to whether or not anyone would know of any specific issues that I might encounter with this swap before I go buying anything. Any input on this would be appreciated including suggestions for which might be the better computer to use.

Thanks,

Did you manage to ever make this work?

Did u figure this out I was wanting to try the same thing being there way more tuning ability

E38. 2009 OS.
You can run big injectors without doing the double stoich and no permanent codes