If you paint your AR with dura coat, is it permenantly on or could you take it off if you don't like it later.  If you can't take it off how many coats of dura coat is to many, lets say you do it one way then change it after a while and then again and again.

it's removable;  i've had a few wear spots on my lowers.  it's a good finish IMO.

If applied with a airbrush, DuraCoat goes on in a very thin coat, and as such can be done over again and again.
The only problem would be painting a part that has tight tollerances, such as the bolt carrier.
As for removing it, I think that would be a major job, I have painted 6 rifles and 3 pistols in various schemes, and have never seen wear once the paint has set after a couple of days.
For a good info source on DuraCoat, check out Lauer"s site :
www.lauerweaponry.com/