Yes it can be done relatively quick also , that is if the old pipe isn't to far rusted to take off easily, and both pipes have the same fitment. Make sure you saturate all the bolts and nuts with some kind of penetrating over night. The hard ones to get off will be the header or manifold nuts off of the studs. If these are rusted to bad they can be a pita.
If I had to change mine out right now and had another pipe for it, I could go out and swap it in about 1/2 hr. Of course I already know what tools I would need to take under there with me, so I wouldn't have to climb in and out to find the right sized socket. If you have never changed a mid pipe out it will take you a little while but not to long.