We have mounted the tail light PCBs into the enclosures using standoffs and stainless steel hardware. We also used 16 AWG automotive grade wire using the original color code that the car used from the factory. As can be seen in the photos below the new lights are incredibly bright and will serve the car well.
The only modification that we will be making to the lights is the driving light intensity. It turns out that we are not dimming the LEDs enough when just the marker lights (or driving lights) are on. We used a decade resistance box to try different values and found that 10 Ohms dimmed the lights sufficiently. We will use a 10 Ohm high power resistor inline with the driving lights to dim them to the appropriate level.