Okay, well, first give us your tank size, and the other tankmates of the puffer and SFE...
Yes, Porcupine Puffers can get very large, and generally need a tank no less than 75 gallons.
They are carnivores and should be fed mostly hard, meaty foods, such as raw shelled shrimp, clams, mussel, lobster, etc. The hard foods help them keep their teeth filed down, much like a hampster.
My Valentini Puffer, Diddy, also loves frozen mysis shrimp and frozen Emerald Entree. He even goes for New Life Spectrum Pellets and Formula Two Algae Sheets/Pellets.
Most Puffers are generally not reef safe, but it all depends on the temperment of the individual fish, and also depends on how well-fed they are. My Puffer likes to mess with the hermit crabs and snails every once in a while, but does not mess with any mushrooms or zoo's. He also does not bother my CBS, but he might bother a more active/visible shrimp, such as a Cleaner or Peppermint, if he got the chance.
All Puffers are messy eaters and should be placed in a system that has adequate skimming and filtration.
Puffers are very intelligent and learn to recognize "the hand that feeds them." Some will even spit water at you from just below the surface, which is a really funny occurence.
I hope you enjoy your new fish-friend. He/she will probably become your favorite in no time
If you have any more questions, please do not hesitate to ask!