Reply to Audio 8 with traktor pro 2

Hello everyone, I was hoping to get some assistance in regards to the audio 8 soundcard. I currently have the s4 and got the free TP2 upgrade. However, Im believeing of buying a used audio 8 soundcard with hopes to use it with my already installed traktor pro 2. Is this possible? or do I need to buy the s4 traktor scratch pro upgrade? Thanks for the help