(Redirected) Dell Alienware Area 51 new model

I purchased a dell alienware are 51 desktop computer I just got it delivered on Friday.  I want to add another Nvidia 980 gtx card to this but the SLI Bridge comes in 3 different sizes short, medium and long.  What I am trying to find out is what size bridge I need.  I cannot find a picture of hard drive so I do not know if the pci express ports are side by side or is there a regular pci port between them.

http://www.geforce.com/hardware/technology/sli/bridges