That might be a good option. I would for sure keep the HFC (to stay semi-legal and "save the environment" and all) and resonator or your ears will hate you (eventually).
I chose the CPe 3" catback but with a Nameless Performance 3" mid-pipe with a HFC and resonator and kept the OEM down-pipe. Really wakes up the car when you add a good tune.
I kept the stock down-pipe due to replacement cost ($$$), the pain of getting the OEM one off and my belief the turbo needs a touch of back-pressure when using the opened up 3" exhaust to keep decent low end torque for daily driver's like me. YMMV