first of all, until recently it was still hard to find the original. It will be hard to get this lens any time in the next few months. Ignoring that, it was said earlier that it will cost $1200. You could get a d3200, get a used og 11-16, and keep the d3100 as a backup, or sell it and get more glass etc. While I don't know your whole setup, and whether you do photo or video, it seems like there are better ways that you could be investing the money. Also, I understand that you want AF, I know the whole focus motor thing, but do you have any idea how deep the dof on this lens is. if you stop it down at all, virtually everything is in focus. just a few things to consider