You've been busy. OM's are nice units (I was on the fence about getting a squirt a few weeks ago myself). The spa flex is awesome, eh?
Since you asked for feedback...
All of the elbows are going to add a good bit of head to the unit. I'm not sure if there's any great solution given that everything is being fed through the window. Double 45* elbows would have been better than 90* degrees but it looks like it's all glued up so it might not be worth the effort to fix. You can play around here to get an idea of what you're losing (
http://www.reefcentral.com/index.php/head-loss-calculator). You'll gain a bit anywhere that you can remove any of the hard bends and replace with a piece of spa flex.
If you can get a straight shot to the intake of the pump you'll lesson the chance of cavitation (would cause a micro bubble problem in the display). Being that you're going downhill from the sump it might be OK even if you do have to use an elbow. Again, spa flex would be better though if you do get in a bind.
Most importantly, you're really going to wish you had installed enough ball valves to isolate both the pump and the OM for servicing. Granted, there are ball valves behind the tank but it's going to make a pretty big mess when the time comes. Also, the easier it is, the more likely you'll be proactive on service. I tried to find a good photo but couldn't. You put the ball valves on the unit that needs to be isolated, not on the tank (hopefully that makes sense).
HTH! Keep up the good work.