To go throught he firewall just pop the hood and look on the far wall, you will see a rubber plug that is just, well a plug. You can cut a hole in the plug (what I did) or just remove it (I wanted it water tight) If you start feeding the power wire through you will find it coming out from underneath your dash. The best way to hide the wire is under your carpet or that plastic that runs on the bottom of the door.
2001 Ironman Daily Driver... 3.5" suspension lift (OME912 springs and 1" spring spacer), ball joint flip, 1.5" front diff. drop, 33"x12.5 TrXus MT, 16x10 Eagle Alloy rims, Interceptor, PV muffler, K&N air filter, Alpine Supercharger, Bilstein shocks, and some trimming.
2000 Ironman Project LS-1 VX... very slow progress but someday....... ohhhhh someday......