LED question

[Oilers]

I was reading about SOL LED on the BRS website and it says that you need 1 SOL unit for every foot of your tank. Is that true? My tank is 5x2x2. Does that mean I need 5 SOL units? That sounds too much to me.
Also, the SOL unit is $400 each. The Radion unit is $800. Is the Radion much better than the SOL then? Is there a kit to hang these LEDs? I saw them being hung from the ceiling at the stores and I don't want to go that route.
I am looking to convert into LED and it seems to be an hefty investment so I just want to make sure I am doing it right. Anything else you can tell me is a bonus. Thanks for the input.