MDMA is MDMA is MDMA. If you have MDMA, you have MDMA. It doesn't matter if it's in pills or power. Both can be easily cut with shit, so test your product.
caffeine pills really do work but as mentioned above (several times) be careful as if you take too much you can feel really jittery/wired in a nasty way.
Take a qtr/half of a tablet and if you want more take another qtr etc - mind you the mgs of caffeine change so much between brands so watch out.