Thanks bro. There is only a minimal price difference between 2GB and 4GB variants, So I chose 4GB.I'm using RPI 4 2GB + topping E30. Works flawlessly, I don't think Moode or Volumio require more RAM. I've added a digione, but I can't speak to whether the Boss2 would have been a better path to take, it does seem a bit more economical
Do you use a separate power supply for topping E30 or the RPI's USB port?