Correct me if I am wrong on this theory.
Besides Modafinils effects on other neurotransmitters lets just talk about dopamine. Modafinil is a dopamine reuptake inhibitor meaning when the brain normally boosts dopamine it will then block an excess of dopamine. So Modafinil interferes with this blockade allowing more natural dopamine to be present.
Amphetamine will basically push dopamine out of the synapse.
So if you take Modafinil first and your brain naturally has more dopamine available wouldn’t taking an amphetamine push even more dopamine out so you get a better effect?
So perhaps the best method of action to get the most out of dopamine would be to take Modafinil in the morning, then amphetamine a few hours later and perhaps some precursors at night like tyrosine?