Hmm where do I start...
Let's try with the fact that the Quran now is identical to the original
Firstly there are numerous evidences to prove the Qu'ran is incomplete as it stands today. Abdullah ibn Umar had this to say in the very early days of Islam:
"Let none of you say, I have aquired the whole of the Qu'ran. How does he know what all of it is, when much of the Qu'ran has disappeared. Rather let him say "I have acquired what has survived" (As-Suyuti, Al Itqan fii "Ulum al -Qur'an, p 524)
There are many records of verses, passages and even whole sections said to be part of the Qu'ran which are no longer there.
For example
Whole sura's are missing.
Abu Musa al-Ashari, a close companion of Muhammed and one of the earliest authorities of the Qu'ran is rorded as teaching the Qu'ran reciters (quarra) in Basra
We used to recite a sura which resembled in length and severity to Sura Bara'at. I have forgotten with the exception of this which I remember out of it? "If there are two valleys full of riches, for the Son of Adam, he would long for a third valley, and nothing would fill the stomach of Adam but dust. (Sahih Muslim, Vol 2, p 501)
The tradition is preserved in two of the most recognized collections of the sayings of muhammad. Next to the Sahih_al-Bukhari the Sahih Muslim is regarded as the most Authentic record of his life. Other companions also reported that Muhammed used to recite the verse quoted but were not certain whether it was from the Qur'an or not. (Anas ibn Malik, Ibn Abbas)
The Sahih Muslim mentions others, which i won't quote here to keep this post at least manageable in length, but do look at it yourself.
The Musabbihaat are a group of five surahs (57,59,61,62 and 64) which begins with the words "Let everything praise (sabbahu or yusabbihu) Allah that is in the heavens and the earth.
Now see what is said of them in the Sahih Muslim
"And we used to recite a surah which resembled one of the Surah's of Musabbihat and I have forgotten it, but remember this much of it. "Oh people who believe, who do you say, that which you do not practise (61:2) and "that is recorded in your necks as a witness (against you) and you be asked bout it on the Day of Resuurection" (17:13) Sahih Muslim, Vol. 2, p. 501.
Notice two things in both these examples... 1. the speakers all of whom were Muhammeds companions, said 'we used to recite.. BUT I HAVE FORGOTTEN" and 2. Even the Qu'ran may not contain the full revelation as given to Muhammed.
There are many verses missing too
a verse from Surah 98, discussing the Religion of Allah as the al-Hanifyifyyah
the stoning of adulters to death is missing. Surah 24:2 teaches a lashing with 100 stripes for adultery, whereas the original stipulated that those who commit adultery should be stoned to death ( (Muwatta Imam Malik p 352)
Notice how Sahih al -Bukhari describes the reason for it being left out in vol 8: p 539
"that part of the scripture revealed to Muhammed was the ayatur-rajam (stoning verse) and that they memorised it, understood and recited it. he added that he feared people in time to come, on finding no mention of that verse in the Qu'ran would forget the ordinance.
Naaji, I have a couple more examples which I won't include at this time, though am happy to send them if you would like to do some investigating of your own. When you talk about the textual integrity of the Bible, please also understand that the Qu'ran likewise can also be looked at.
Carol