Pulling wires through the Yaris

[gravylegs]

This post is half question, half warning.

Yesterday I finally got around to pulling the power, RCA, and remote turn on wires from the battery/deck. The whole operation was fairly simple.

I pulled my power wire through an existing grommit hole on the passenger side floor. You pull back the carpet, then pull back the second carpet, then lift out the styrofoam floor piece (which I was suprised to find!), and there is a tube running from what looks like the HVAC right through the floor. I think it is an air intake. I put the wire outside of the grommit, and then wedged the grommit back into place holding the power wire snug. This was the only easily accessible hole in the firewall that I could find. My question here are: What is this tube? If it is an air intake, it is sorta scary that it is sucking my heating/cooling air in from the engine bay!

From here I pulled the wire over to the passenger side (pulled off the trim from the kick panel to the plastic panel that divides the front from the back) and ran it along the side of the car all the way through to the lift. My questions here: putting the trim back on the bottom of the door is really difficult! I had a REALLY hard time getting the carpet to hook back onto the clips that hold it in place, and then when putting the trim back on it simply will not clip back on. It stays in place nicely, but it definitely isn't right.
Any suggestions?

Stereo sounds sweet now...

Oh, and the warning part is "be careful when trying to put back the carpet and trim"