No you dont' want to stack them. Pump HD has yohimbe and works great with creatine/beta alanine. Snephrine is just way to catabolic i dont even use it. C4 doesn't have it anymore or at least as much. Synephrine is more for looking good around a contest or photo, but also has a wierd effect on the heart.
Safe Stims: Caffeine, Yohimbe