I just traced out the vent on the ceiling assembly and then used a 3/8" drill to create a hole on the edge of the cutout. That allowed me to then insert a jigsaw with a metal blade (cuts the plastic better) into the 3/8" hole and cut the circle out. The new vent attaches with 4 screws that are hidden when the vent insert is popped into place. Looks factory when you're done.
Vince
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