go through the steering shaft boot. Just poke a hole and run the wires through there. If you have a boost gauge....you dont need to leave the pass compartment. Just get a tee fitting off the line that runs to the stock cluster, run the power, ground, and lighting wires in the car. I made my gauges even dim with the stock dimmer switch. The air/fuel is useless IMO....it only reads narrow band and trust me, you'll end up ripping it out after a few weeks cause all it does is flash useless colors. That too can run all inside the car. For the signal wire, just run it to the computer where the o2 sensors come in. Peice of cake.