with all the modding i've done, the pump that's in there is probably pretty clean! if you haven't mesh modded it yet i would think it's probably ok. I noticed the mesh mod impeller had "stuff" in it vs. nothing in the nw. I wonder if Koral ever got his air meter?
As far as that pipe goes... it's just a piece of their crazy metric sized plastic pipe that had an end on it and then they cut a section off the top to make a trought. I don't know if we'd be able to duplicate exactly, it looks like it goes all the way to the back wall which would be hard for us to do. I don't know what size pipe would fit in there, possibly a ground down 3/4"? Here's a rough pic of what it is though just in case you're still having a hard time seeing it:
