Opinions - Stimulant Research Chemicals

[KyleinMN]

I'm a big fan of psychedelic RC's but I've never tried any non-psychedelic rc's that are more stimulant in nature and I have some questions about them.

I work 2 jobs and I'm a full time university student so I often don't get enough sleep. I start work at 3:45am and by the time I go to class I'm very tired and have trouble focusing and often find myself on the verge of falling asleep in my chair or just kind of zoning out (not due to lack of interest in the lectures I should add). I'm looking for a stimulant not purely for recreation but to help me stay alert and focused while studying or during particular busy days. I don't care much about euphoric properties as long as I'm alert and focused but it certainly wouldn't hurt. Obviously drugs are not the most healthy remedy but I only plan to use them when neccessary (staying up all night to study for a big exam, etc).

I've done a little researching and I've narrowed it down to a few chems that seem like they may be very useful. I know not all of these are RC's in the way we generally talk about them but I don't see the point of starting another thread in the amphetamines section.

4-fluoroamphetamine
4-methyl-aminorex
methylenedioxypyrovalerone
dextroamphetamine
methylphenidate

Any opinons on which may be the best for the stated purpose or any good ones that I missed? Obviously anything with a psychedelic feel wouldn't be a good choice and I want to avoid anything neuro-toxic. Physical and mental dependancy won't be a problem since I plan to reserve this only for times deemed necessary and I've never had problems with any sort of drug dependancy issues. Thanks for any suggestions!