Piracetam will probably not help the amount of serotonin or something like that, it just doesn't work that way. It enhances trips though, for better or worse.
I'd say don't do them both in the same weekend and make it a single special experience each time instead. The order is no good IMO like the other said. You could reconsider doing an evening/night trip and rolling during the day, maybe it is not what is usually done but both are quite fun and can be special in their own right. See the MDMA as an empathogenic psychedelic instead of a night-time party drug and you might have an emotionally opening therapeutic beautiful experience. It's a little different than at a party for instance but I might even like MDMA more when done at home during the day. A great party is one thing, but a magical special experience in all the peace and mellowness of the day... wow
I've used piracetam only with LSD, not mushrooms. It was different, definitely enhanced, stronger in a way but mostly in a qualitative way not quantitative if that makes any sense. I would still say be careful with piracetam + psychedelics and when doing two intense drugs in a weekend that may be all the more reason not to use piracetam. By the way piracetam may be a better idea for the MDMA than the mushrooms. Not sure though but I think it is an amazing combo. I forgot what thing I combined piracetam with, if MDMA was also ever in there.
Oh I see you were planning to do the piracetam in between the two drugs not during.. hm but still, it's not like a magical cure like that.
Remember that a lot of the nastiness of MDMA comedowns is the lack of sleep and food. So if you want to do the MDMA at night time the sleep deprivation could very well add to a bigger chance of feeling spent or empty on sunday. So: change your plans for night and day time and do them the other way around, or choose one of them for this weekend and save the other. I'd say.