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It's not really clear whether it draws power from the firewire cable or not. It should, but.... Your best bet would be to call them and find out.
 
Yep, it should be fine. I have a firewire 2.5" hard drive being powered by my iMac. As long as it's 2.5" (some 3.5" work over fw800, but let's not go there! :) ), it should work.
 
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