Nate,
The HiBoost kit for the P5 is not "Carb Exempt" The only CARB certified kit for the P5 is the now defunct FM kit and a Mazdaspeed OEM kit. Now, that does not mean the HiBoost kit won't pass smog if you hook it up to the machine, in fact, thanks to haltech the possibilities are hight that it would pass smog, you just need a tech that will overlook the very obvious turbo kit and test the car.
As for an actual kit, You can't go wrong with HiBoost or Mental Addiction. The new MAMotorsports Street Sleeper kit looks very nice.