Swapping my wheels, basic questions

[pauljdh]

Ive just picked up a 2020 V90 with 21" wheels.
Whilst they look great I'm not keen but I wanted the car and am looking to buy some 18" wheels for winter with some cross climates on it.

If I do, do I need to:

"Tell' the car that it has smaller wheels? (It has switchable driving modes and Polestar mapping)
How do you replace the tyre pressure sensors?

Any other considerations? Looking for a 5 x 108 bolt pattern

Thanks all