First off, stoning is in Hadith/Bible, not the Quran.
Second, it's flogging (not stoning) and it's for both MEN and women.
Third, and that's the most important part, it was made virtually impossible to prove fornication/adultery... rendering it a suspended sentence.
If the Qur'an was sent to confirm the previous Books, in this case, the Torah, then why doesn't it contain the injunction of stoning for adulterers? I mean, it's the same 'kitab,' isn't it? So why isn't it in there?
And at the same time, was stoning part of the Injeel? I think Jesus did not mandate such a practice at all, and yet the Qur'an says that 'there is no change in the words of Allah.'
Not trying to catch you out or something, these things just don't make sense to me, at present.
And another thing, are you a mu'tazilite?