Uh. Mushrooms work almost SOLELY on serotonin (to exert their psychoactive effect). MDMA, on the other hand, has a very complex pharmacology that requires release of serotonin, dopamine, norepinephrine, oxytocin, etc.
All psychedelic drugs including the psilocin and psilocybin in mushrooms are 5-HT2a agonists. 5-HT is short for serotonin, and the 2a is a specific subtype of serotonin receptor. Most 5-HT2a agonist psychedelics produce a tolerance effect that makes it almost impossible to 'trip' again without doubling or tripling the dose. This tolerance effect wears off over the course of 3-7 days.
MDMA on the other hand, has very little 5-HT2a agonist effect. Some of the visuals and cognitive enhancement that MDMA produces would be blunted by 5-HT2a agonist tolerance.
So the real answer to your question is, if you normally get and enjoy visuals on MDMA, you will probably not get much if any visuals if you ate shrooms two days before MDMA.
Most of MDMA's effects are from the release and reuptake inhibition of 5-HT, dopamine, and norepinephrine... just like amphetamine. If you had taken meth or amphetamine two days before, maybe MDMA's effect would be blunted from a cross tolerance...