the guys are right, but I would add, if you are going to pay someone to do it, find a "good"chassis shop and pay what they want to do it. If you try to save a few bucks here, all your expensive parts will be wasted if they are not installed straight and squaure.
Building cars, even back halfs are not cheap anymore, but when they are done correct they work well and are a piece of art in my opinion...