I want to upgrade my existing gauges...to AutoMeter. If i am going to do this....first, how do i mount the gauges. Second, What kind a material (aluminum, steel, diamond plate, etc.) should i "face" them with. Thanks.

They usually come with brackets or you can order some so you can drill them to the dash. You could also order some universal gauge pods and mount them on the pillar F & F style. Facing them is personal preference.