1000W ATX supplies are a little on the $$$$$ side and if you don't need that much power, then it is a bit of overkill. I would stay away from the "bargain" supplies. With the rapidly changing demands we put on them during the show, the cheap ones tend to show you why they are so cheap which may not be so good for your show. Yes, each of the units will need its own supply. While there are ways to have them share a supply, it actually costs less to have two 700W supplies than one 1000W and the two 700's have more available power.