Catback = keeping stock headers and cats (catalytic converter), then replacing/upgrading the muffler and final section of pipe till it reaches open air.
so everything from the edge of the cat. back to the end of the tailpipe.
Keep researching and using google to find the system you want. if money was not a factor I would recommend replacing everything! heads, cats muffler the whole 9 yards!
which system you choose boils down to what sound you like. There are plenty of CA boys here who have gotten passed smog checks with complete systems. Search it on the forums and you will see many posts about this.
read up on the arguments of how much low end torque each system will drop, if any at all, for the HP gain.
Hear the system in person if possible as you might not be familiar with the drone enemy that is prevalent in aftermarket exhausts on the box.
In terms of cats. they can be either more restrictive and leave a better CO2 footprint, but bog the engine down a bit. Or they can be inverse of that. (CA smog issues lol)
Good luck, keep reading as much as you can on the issue, dont forget to search and keep asking questions.
MORE IMPORTANTLY
if you do get any system we will never believe you! unless you post vids/pics
