I mounted mine in place of the sunglass holder in the overhead console. This is a 2000 SR5.
1. First I removed the overhead console (one screw) and pulled out the roll pins holding the door to the console.
2. Determined the location at the rear of the console. It happens to be angled nicely downwards if you push the gauge all the way to the back. Roughly a 45 degree angle.
3. I drilled a hole in the back of the console large enough to pass the cable through and plug it into the gauge.
4. Drilled 4 small holes in the ScanGauge case (take it apart first!) and 4 matching holes in the rear of the console. These are for zip ties.
5. I apologize for the lack of pictures on this part as it was the most difficult during this project. I had to progressively feed the zip ties through the gauge as I tightened them from the inside of the console.
6. I ran the cable through the headliner and behind the A-pillar trim so it is completely hidden. I had to extend the cable by a foot or so using a female-female coupler and extra cable.
With a little patience I was able to get a very secure mount with this method. This was a requirement of mine as I did not want the gauge to move while driving or when pressing a button. I also did not want to take my eyes off the road to view the gauge. I am quite pleased with the result and I think it outweighs the loss of the small storage compartment.