You can pick any of the various brake lines or other tubes running the length of the car and use copious amounts of zip ties, but that leaves you with a long stretch of exposed wire; very vulnerable.
As for going through the fire wall, don't drill a new hole:
There are two grommets up at the top of the fire wall next to the cruise control box. Take the plastic covers off the windshield wiper linkage area, and there are two grommets, one into the engine bay, and one into the passenger compartment, directly across from one another.
Punch holes in the grommets, and run the wires through there. I mounted the junction box for my neons on the fire wall right next to that grommet. You can use one hole for the switch circuit wires and the rear tube wire.
You'll also have to punch holes in the fabric liners on both sides of the fire wall, but that's no big deal.
Peace
Jed
Oh yeah, I mounted the rear tube right above the wire mesh in the rear valence; putting the screws into that hard black plastic bumper support. The front tube is mounted to the plastic duct panel directly in front of the air dam.
