I did not going to read all posts through, and though i see he was countered, yet i did not see the argument that the texts where changed, while Islam also believes the Torah was changed, and somewhat affirms the Injil, though there is wide spectrum of variance in the attitude towards the Bible among Muslims.
I didn’t see much of a counter to his posts; his challenges were pretty open and specific, and replies to them largely vague and conjecture-based.
That said, the Islamic opinion is derived from specific verses in the Quran, and that significantly narrows the spectrum of opinion amongst observant Muslims.