Brake-a-way is any convenient spot on your bumper. Actually if you can take a picture of your bumper it would be easier to tell. If you want it to hide away, you only need one screw so it will pivot when not used, if you don't care, mount it straight away, toward the tow vehicle. As far as going through the firewall, what kind of system do you have, what's going through the firewall? I have an airline that goes through my wrangler to the extender for the brake pedal, I just looked for a clear spot without knowing what kind you are using it's hard to say.