Seconding what Heartcore said- They suck.
Methamphetamine is VERY closely related to amphetamine, just smoother and stronger, but the mechanism of their addictiveness is EXACTLY the same. You are splitting hairs.
Also, welcome to the world of biochemistry....your biochemistry is unique. Just because your friends react to speed that way doesn't AT ALL mean you will....for the most part I find what GOD said to be true.
Dabbling with amphetamines as you are I doubt you've seen the real negative face of it.
It's not pretty.
I consider all non-psychoactive drugs that are popular such as speed and opiates as dominator drugs, per McKenna, and see absolutely no reason why they should be propagated.
There are a lot of interesting substances out there, some moreso than others, but they're all more promising than boring old speed.
Psychedelics have the opposite effect, they get BETTER as time goes by, and they're not addictive.
Also, chemically Adderall is a racemic mixture of three different types of amphetamine salts, and the reason for this is one that may surprise you;
Since adderall is prescribed for ADD/ADHD, the amphetamine level must remain elevated in the blood for extended periods of time; your body would normally detox a single salt form of amphetamine much quicker than adderall doses, so in this light, adderall is seen for what it REALLY IS; a time release form of amphetamine.
If meths effects are just longer duration and a stronger rush,
you're halfway there already and didn't even know it.
You're playin' with fire, man.