All those who oppose the KJV position, I am curious. Do we have a final authority we can appeal to for all matters of life? If so, where?
We already have had this out, we have no "Final Authority" version, you can not prove that such a thing was meant to exist. The logic of having a Final Authority version is flawed, as we have to have a "final authority" version in every language, and then we get problems of do they mean the same thing.
Gods word has been successfully preserved from the original authors through the thousands of years with an unprecedented number of copies and translations in existence, no other work from antiquity can touch the Bible texts for age and quantity.
Most of the history we know about Roman empire comes from a copies of which the earliest in existence a just a single copy that was published hundreds of years after the original came out.
The errors you speak of in NIV etc are not really errors, just as the "errors" pointed out to you in the King James, they are not errors as such, just difference in interpretation. These so called errors are not exactly damaging to Gods word anyway.
The issues of number of days someone did something or quoting Nebuchadnezzar are not damaging to the Word of God, if a new Bible comes out that says something like - "Jesus spoke to the people and told them that although they rejected him they would still get into eternal life if they did good things", then we know that is false as we have dozens of other versions all telling us something different.
If we have a single Bible that we can only use, then that is dangerous as things can get re-written and no one will know, but by having dozens of different versions spanning hundreds and hundreds of years we can clearly see the heresy and the attempts to corrupt Gods Word.
I see no Heresy or attempt to pervert Gods Word in the NIV nor do I see it in the King James.
Finally I will end with the point that you have not proved there really should be a perfect Bible we should all read, that is before we even get to the King James being that perfect Bible.