What do i need to run traktor with my 2000 setup?

CDJ2000'S ARE YOUR SOUNCARDS, USB CONNECTION FROM CDJ INTO YOUR LAPTOP VIA THE LINK FUNCTION

But do i need to but traktor pro scratch 2 software and the tracktor audio interface, or just the traktor pro scratch 2 software on its own? :S

It all comes down to one question - latency.  If you want to scratch, the latency within the MIDI system is too high so you'll want to use timecode.

If you want to do any scratching, you'll need an audio interface for use with the DJM2000 as it's not Traktor certified and doesn't have the ability to receive audio signal from more than 1 channel.

If you don't want to scratch, you can use the CDJs as MIDI controllers and have Traktor output the audio to the DJM2000.

I found this post by looking for what I need to run Traktor with CDJs. I will have to correct Pulse with his answer. CDJ's are not just midi controllers. They use a technology called HID. The HID is a far better resolution over MIDI AND timecode. Think about it. A timecode CD is a digitial device that has to be interpreted before the audio is output...which my nature produces latency. Then that signal is interpreted again for transport control of the timecode signal. It passes through two phases of digital conversion before it gets to output the audio. HID however is more direct. It's still digital, but everything you do is a direct command to the software while timecode is a relay. HID is more advantageous for its accuracy and the open use of more features of a CDJ. There is no comparison with the limiting technology of timecode.