That's the same pump I'm using, good choice. I considered a few internal pumps. As in a few - Tunze Silence & Ehiem pumps to feed everything and return to the DT. Combined they would be less watts and heat to the tank than a Mag 18 or the Dart. But, the Dart will run everything, absolutely everything, through a manifold and with a slight restriction draw less then the 160 watt max rating.
EXACTLY and from what i've seen they look very compact as in around 10 pr 12" which SHOULD fit under the Stand. None of my electronics will be under the stand so I can utilize that space however I want. I plan to have a small L shaped attachment off to the side that I can store some stuff in. I also plan to Paint a nice Piece of PlyWood or get some PlexiGlass to sit on TOP of my sump's Return section to make a shelf to sit a Coralife Calcium Reactor on.