First of all, you're wrong, but we'll get to that in a bit. More importantly, you still haven't answered my question.
Why do you need to downgrade it? You have not explained to us why you need to downgrade your Wii, but you expect us to tell you which choice to make?
Are you trying to run backups? Homebrew? 360 Games on your Wii? There's no way anyone can help you if you don't tell us what you're trying to do, how much money you're willing spend, and how many hoops you'll be willing to jump through in order to do it.
Omg do you know how much money I would spend if that was a thing? Especially if you get to assemble the gundams somewhat like those old model toy kits. The answer is zero dollars. I would spend zero dollars. It would still be so good, though.