I asked this question before:
and did some measurements, at least for the M.2 SSD.
There is very little clearance here. I concluded that even 1mm might be too thick.
Others have tried this and said that it did fit. I don’t know whether it made any difference or not.
As for the RAM…you would be the first. I don’t personally think you’d see any benefit and if it presses down hard on the RAM you may get problems, but that’s my personal opinion. Certainly no more than 1mm here as well.