The first response from middle west was not accurate. you asked about upper he talked about lower. buying a "complete upper" vs DIY depends on who your getting the "complete upper" from, same as the DIY. look around and find a few of each category you are interested in and get back to me and ill help you narrow down the best option for you. I am a Gun smith and work independently for several national suppliers to the big name sin the market, i build the kits they sell.