Thanks for that Nimrod, but I've already read that- I wasn't being clear.
For weight loss, yes, adding the aspirin extends the effects of the ephedrine and caffeine; if you're trying to lose weight, then maintaining a heightened thermogenic state for a longer period of time equals more burned calories.
But for preworkout stimulation, you don't need the EC to last even 3-5 hours. I had read that the aspirin was a safety measure because it ameliorates the blood cells' tendency to adhere to vessel walls. This is important because ephedrine's redeeming studies have indicated that the deaths attributed to ephedrine were caused by: 1) most likely an overdose, or 2) consumption by individuals with pre-existing coronary blockages.
In other words, the risk of ephedrine is somehow related to vascular problems, particularly those who have trouble moving blood through the heart. If I take an aspirin, I might have greater difficulty controlling blood loss (so don't take it before boxing, that can be a hassle), but I'll be that less likely to develop a blockage in my vascular system.
But shit like this can be tricky. I can't remember any conclusions being drawn from that study besides what I've already stated, so it might work as I have inferred, or it might be something altogether different; maybe people who are genetically predisposed to have coronary problems share some trait in their genetic code that also causes them to die when they take ephedrine. I don't know.
The body is huge.