1.
works through release of excitatory chemicals called catecholamines. These catecholamines, which include adrenaline, act on cellular receptors (mostly beta2s after they down regulate the jolt dies and it effects mainly beta3s which is said to still be effective for fatloss) found in numerous body tissues and are responsible for stimulating lipolysis (fat burning), increasing heart rate, dilating bronchioles, decreasing appetite, and increasing alertness.
2.
They are the same thing read the back label and you will see the active ingredients of any good fat burner is ephedra or norephedrine stacked with caffine. Neither is safer than some people get less sides for a norephedrine based formula for some its the opposite. One source I read stated that deaths with ephedra have all been with use of over 250mg. This was from a non product selling or bodybuilding site. This stimulation of the cells is (gah brain lock) multitive (not the word I'm looking for) with the addition of caffine. I.g. if caffine stimulates the adrenal release by 1 and caffine does it by one the net results ends up being 3!
3.
Ehedrine HCL at the drug store, caffiene at the same place or even wallmart, aspirin samething. Low dose (though I would just leave the aspirin out its not well documented to show any real positive effect)
4. 20-25eph 200caffiene for a pre work out jolt. (some only contain half the caffiene the best ratio is supposed to be 200mg for every 20 though but if you don't want so much caffine) (some also do a double dose for preworkout)
Some reccomend the 20/200 dose or 20/100 dose 3 times a day. I personally don't like it. I believe the best use for the stack is prework out energy. The actual amount of calories it burns by itselt is minute but the energy it gives to let you hit the gym hard and heavy and keep your appetite surpress as just a pre workout jolt works great. It will also allow you to use it for a longer period of time without losing the energy feeling (which is considered a side effect by some companies, but most love it and don't want it to go).
Start off slow if its your first time ever, you know how you may react to it. If the dose can be split up take 1 pill wait 20-30 minutes if you feel fine go ahead and take the rest.