The Quran as a Criterion
You understand that the Quran is referred to as bainah and can't get away from that. You understand that the Quran is a criterion over question. You understand that when Prophet Muhammad (sallallahu alaihi wasallam) was reading aspects of the Torah, he told them that you have been given something, you don't need to read this, which is the Quran. When the Prophet Muhammad (sallallahu alaihi wasallam) saw reading aspects of the Tawrat of the time which were preserved, some aspects were preserved, and he was reading it. He said that you've been given something which replaces this.
The point is this: The Prophet (sallallahu alaihi wasallam) mentioned in a hadith, "Do not belie them and do not believe them." Which means that there is something in circulation from kab about which you may remain agnostic. If the Quran contradicts it, then the Quran takes precedence.