Sounds like you have done a bit if research already which is great, a sump is good however they are definitely not needed. Diy led would be fun, im pretty keen on that myself. Pumps, get a wp25, have great reviews, quite powerful, excellent wave action when you set it to that. Comes with controller and stuff so pretty easy to use. A much cheaper alternative to the vortecs and people claim them to be better due to the adjustable head and the fact that they sit completely in the tank and the sound of the motor is muffled by the water as opposed to the vortecs where the motor is on the outside of the glass and not exactly quiet. Depending how well the spread is on your light, you could put the unit towards the back but ideally above the main body of coral you have as its the coral that need the light, fish don't mind. If your coral is up against the back of the tank then obviously you won't have a problem with the unit being at the back. Good luck and patience is your friend with marine 8)