Depends on what you want to do? If you buy a system now you will also need to get the Edge monitor to delete codes on start up unless you don't mind having a CEL on all of the time. If you want to increase your HP with the Edge, then go ahead and get the whole system now.
If you don't want CEL's and you don't have any other reason to buy the Edge, then wait a month or so and get the code free system.
Some people that have deleted DPF's are seeing no or little MPG improvement while others report a 3-4 MPG improvement.