As for the software itself, Scratch Duo is pretty much the same as Traktor Pro but just with some lesser features. Prices on Traktor products are cheap at the moment due to a 50% off sale that Native Instruments announced at the end of last year but stock is becoming hard to come by now. If I were you I would try and get my hands on Traktor Scratch Pro from somewhere. At the moment you could pick it up for about $100 or so more than the Scrath Duo pack. Than you have everything you need if you decide to use timecode cd's and you also have the 4 channel sound card. If you buy the Scratch Duo bundle you can still use timecode cd's but just at the moment with the prices you would be crazy not to buy the better version. I recently purchased Traktor Scratch Pro from JB HI FI for $350, full price sticker on the box was $890. So rather worth it given its full retail price. Other option is you could buy the Scratch Duo pack and buy the upgrade for the software so you are running Traktor Pro. You can buy the software from Native Instruments website at a discounted price because you have the Scratch Duo bundle. Sorry for the long post, I went down this path only a month ago. Good luck and I hope I haven't confused the hell out of you.