On mine I just ran it down thru the wheelwell. Keep it ziptied tightly, then just run it thru the sideskirt. I have 4awg wiring and had the entire wrapped with hard plastic to protect it and haven't had a problem yet. It really is MUCH easier than putting it thru the firewall (the alarm system i have takes up almost all the space in the holes) and as long as you don't plan on driving thru water 360 out of 365 days or off roading you don't have to worry about it getting damaged at all.

 

uhm i believe theres 3 grommits in a 2000 civic The one behind the fuse box, the one on the drivers side, and theres also one beneath the battery if im not mistaken *DONT QUOTE* i havent pulled my battery for almost a year and a half due to the bodyshop taking their sweet *** time with my car. Either way, Be sure if you drill a hole, to buy another grommit or find one somewhere, otherwise raw wire coating + drilled metal = grounding the system from road vibrations.

 

there's more then 3 grommets on any car but the grommets that are listed for installing aftermarket equipment and that are not being used by the car are about 2 some year model civics 4