Yeah, you need to look at forums for specific makes and models.
I knew I wanted a Subaru Outback and the Outback Forums were massively helpful. There's long threads on there where people post prices for trimlines and which dealership has the best deals in the country. People on those forums will fly half-way across the country to get a couple grand knocked off an Outback.
https://www.subaruoutback.org/forums/