Choosing the right card Which graphics card is the right one for me?

Hi everyone. New to proceedings here and I have a question first up. I’m a (just another) disgruntled Final Cut editor who makes broadcast TV so I’m forced to to change to Premiere so I want to up-spec my two Mac Pros (2009 8-core 2.66) to make use of the CUDA technology. All my research points to the Quadro 4000 so easy - I’ll buy that. Only, when I go to B&H there are two options and I have no idea what the difference/advantage is.

Can somebody please explain why there is almost $300 difference and whether I need the more expensive option?

Cheers, Marc