In my experience it was the fuel pump as I had the same symptoms. The regulator is a relatively simple part that does not fail that often. Make sure you have changed your fuel filter lately as that could contribute to the problem.

What is your fuel pressure reading when cold and then when hot? This would extremely helpful in determining the real culprit. The regulator is certainly easier to change (and cheaper) than the pump - you just need a good set of snap ring pliers so the ring can be compressed to remove/install it. Be sure to maintain the order of the orings and spacers when you move them over and do not loose the very tiny bottom black oring (it should stay in the housing). I have pictures of the order the items need to be in in the supercharger install manual downloadable on my site.

Changing the fuel pump requires the tank to be almost completely dropped. New pump and strainer with lifetime warranty cost me around $200.