Earlier quoted context omitted.
> and ghasp talk to real people, potentially a few, at different stores, to get what you need. That's really an issue: if you aren't the hard-boiled, super unemphatic negotiator type you'll likely buy the very first thing a salesperson has invested face-minutes in, if it just gets the easy 80% of requirements/desires right. "Thanks for your time, but I'll go see if there's another offer that is maybe 3% better or 2%…
People in the US were not haggling for anything less than a car in the decades before the internet.
In general the more knowledgeable the dealership/salespeople, the more likely negotiation is possible, especially if you present as a knowledgeable customer so that neither of you are wasting each others' time.