Logitech Z506's VS X-530's

[Noodles :)]

$10 price difference, which would be the better choice(The Z506's being $97 while X-530's being $88)
The Z506 have a green, black and orange output on the back of the Sub, and outside the box they're in it says 6 channel. Would I need to connect the black and orange things to my PC(I know a decent bit about computers, but soundcards and speakers, I'm hopeless with...
The gamespot forums, are slow decided I'd post here too!

 

[ritchynator0]

The Z506, yes.

 

[Noodles :)]

That's what I thought, but mind answering my other question about the plugs?
Cheers man. :3 I can't find it on google. I don't really wanna spend $100 and find out I can't use em.