I wrote an article about the ECA stack on my blog a long time ago and I still see a lot of people asking about it. I've used the stack several times over my years of lifting with good results--it's one of the few "fat burners" out there that actually works.
Just keep in mind that much of its effectiveness comes from the appetite suppressant properties--it basically annihilates your appetite.
Aspirin has never made much difference for me. If memory serves me correctly, it supposedly helps more with obese individuals for some reason.