My install was a 2020. The new 2021 likely has the same A pillar airbags. If so, just remove the bolt under the plastic "airbag" label, and the pillar cover will be able to be moved out of the way. You will see a factory wire channel on top of the airbag itself. Just run your wires in the factory wire channel up the A pillar with the other Tesla wires to the headliner. I loosened the sunvisor mounts on the headliner to put the cables under it. Of course, don't fool with the airbag.Awesome!! I don’t have my car yet, but that sounds super easy. I might even just use a cigarette lighter adapter and plug my old hardwire harness into that if it’s that complicated. But it sounds pretty easy! Thanks!