I have a name for the stack, itself...the individual products could be called 1 and 2, a nd b or something more or less generic that suggests that you need both to complete the stack, thus encouraging sales of both.
I would call the stack "the Synergetic Stack", playing off of the concept that they work synergistically for an energetic result...in the sense that you would have the synergistic "energy" to bang out more reps, more weight, more cardio or whatever else you're doing. "They Synergetic Stack" just has a cool, sientific sounding and clever ring to it, I think, plus emphasizes the need to use BOTH of these products for best results.