on my 2 gauger (on a vert, which the autometer pillar says does not fit, IIRC), i put it over the existing pillar. i put the bottom of the pod at the base of the old pillar, so wires are hidden anyhow (no drilling of the original pillar for wires). i got some real small sheetmetal screws and drilled them in (and painted the heads). you cant see them hardly. i held the pillar in place and drilled as straight as i could. then i drove (by hand with a stubby screwdriver) the screws in straight - it is plastic and mallable.
after puttin the two bottom ones in, it was held up. i put one top one in and called it good. try the bottom first and see how much you need the top ones (that are hard to drill).
good luck and enjoy.