Should I get the Turtle Beach DSS?

I just bought a Turtle Beach PX21, which are my first gaming headsets that I have ever gotten. I switch it back and forth between my Xbox 360 and my Playstation 3, but I use it primarily on the PS3. I have been doing some research and found out that there is a separate system that Turtle Beach sells called the DSS. However, I saw that it is almost the same price as the PX21s that I bought not too long ago, so I do not know if this investment is worth it. Is the value worth the price? Also, I have heard that it turns the audio from stereo sound to 5.1 or 7.1 surround sound. I was wondering how the DSS can make a headset with only 2 speakers create a true surround sound experience. If you have an answer to any of these questions, I would really appreciate a response. Thank you.