No SWIM'ing here on these forums.
Anyways, I'd imagine it'd be more neurotoxic than MDMA alone. MDMA/amphetamine combos are known to be more neurotoxic because of an increase in metabolized dopamine molecules being uptaken by SERTs; it's toxic there so it damages the serotonin cell. It apparently feels amazing from what I've heard though. I've never experienced the combo myself so I couldn't say.
Since low dose amphetamine only block the reuptake of dopamine and norepinephrine, and doesn't cause it to release the monoamines I'm wondering how that would work with MDMA.