CP Racing engine bellypans are designed to replace the OEM plastic underpanels and capture lost fluids/parts during a catastrophic event. With added aero benefits under the car, they install in the two OEM bolt holes on the lower radiator support. The rear section is installed by drilling two 6mm holes through the rear-most subframe on your MKIV Supra. There is a half circle cut-out that allows your wastegate dump tube to pass through the panel as well.
Picture here of the black pan is how it comes, but shown in that picture is the 2" version, not the 1".