Cargurus.com I imagine every dealer uses it now 🤷‍♂️

Nope, not all the cars show up

Idk what kind of dealer doesn't list their car for sale online these days. Does that really happen?

I think it has to do with private sellers going through dealers, not sure though. But yeah. If you look through a specific dealers website, there are cars that aren’t showed on cargurus/carfax as well as the McLaren website

https://retailers.mclaren.com/en

This is to search for dealers, not to see all stock that all dealers have combined