Oh, you may already know this but just in case ... The synergistic benefit of stacking ephedrine and caffeine (where 2 ephedrine + 2 caffeine = 5 in layman's terms) comes when you take them in a 1:10 ratio, eg. 25 mg ephedrine with 250 mg caffeine. How much aspirin you need is a highly debated topic. I know a lot of bodybuilders just use an 80 mg aspirin period, while others like to use a 1:10:15 ratio of ephedrine/caffeine/aspirin. The aspirin's just there to up your internal thermostat so your body doesn't notice (and counteract) the heat, making it last longer. How much you need for that probably varies from person to person. A bit of trial and error may be in order.