I really like the way the light hanger turned out. How much did that set ya back? Probably the least expensive piece of equip you'll every buy for the tank! Looks slick for the cost of some conduit and paint. I'd get some small black zip ties to hide the cords along the hanger arms.
Are you going to stick frag plugs into your foam too? How many GPH flow? What's the plan? SPS, LPS, mixed?
Gotta get some corals under the XM's to appreciate the colors. If you do a search you can find some nice tank pics running them with stunning colors. Are you supplementing actinic lighting of any kind? LED's?