Im putting an ior m2 on my m4 and I was wondering will my front sight post obstruct my veiw through this scope or is 4x enough magnification that I will not even notice the front sight? Or should I try to get it up over the front sight post with some scope risers or something? Thanks.

In my experience (4x ACOG) its not an issue except in very rare lighting conditions. When you have bright light reflecting right off of the front sight base into your eyes. Even then its only and annoyance.

I recently installed an M2 on my M4gery.  I used IOR's high QD rings.  With the scope mounted directly to the flat top you can not see the front sight post through the scope.  I personally did not like this configuration because the scope is mounted low and very far forward.  It is quite uncomfortable to stick you neck that far forward and down when using a full length stock.  To remedy this I ised a RRA tactical carry handle as a scope riser.  This allowed me to mount the scope higher and further back making it easy and comfortable to reach the eyepiece.  In addition to this the holes in the scope rings allow you to use the iron sights while the scope is mounted.  You can see it reasonably well in the following image.  I love this setup, but you may also be comfortable with the low mount.  I know you didn`t ask this much but I figured I put in my 2 cents.  By the way the IOR is a wonderful scope!  

What reticle did you choose?

http://vcufiles.vcu.edu/nebletteb/AR15/PolishedCarrier2.JPG