Reply to Which audio interface will work for me?

First post. Woot woot! I recently transitioned from my Traktor S4 to 2 CDJ 350s and a DJM 400. I'd like to use Traktor Pro with my gear, but I'm a little confused as to what interface (if any) and software (Pro, Scratch, etc.) are needed. I've heard so many differing opinions that I'm afraid to buy anything without a concrete answer. I'm looking at the best affordable option. So far, I've come across Traktor Audio 2 and M Audio Fast Track Pro. Will these work for me? I'm also a little confused regarding timecode vs. midi. Overall, I'm a mess; just a man trying to do what he has to do to survive.