[Vent Problem]

To take them out you have to take out the whole dash (which isn't as difficult as it sounds) there are a few screws behind the radio dash insert, the left grey trim peice and the gage cluster, and the most difficult of them, the two airbag screws (in which the glovebox has to be taken out to reach out under it) I'm sure there is a video online for it.

[Which Engine part?]

Power braking fluid I believe 

[2003 Matrix XR - Suggestions for Interior Touchups?]

I've done something with spray paint that looked clean enough for me