I only have one thing to say: thanks to Güner and his familly, we manage to spend a really great time in Istanbul. The flat was clean and really good located (not far from everything you can need but still in a quiet area).
And Güner has been really nice with us from the beginning to the end.
I recommand it without any doubt and if I come back in Istanbul (and I surely will) I am sure I will come back to you ! Thank you very much !