I also negotiate price to bottom line - out the door.
That way there are no surprises at the end.
Years ago I was wheeling and dealing at a mega used car lot.
I told the salesman I was offering $xxx as bottom line price.
He agreed and I thought it was a done deal.
When he filled out the contract the bottom line on the contract was
not the final price. The bottom line on that paper referenced you back
to the middle of the page where they had added "paint sealer, upholstery
stain block and undercoat". He kept pointing to the last line and
saying this is your bottom line!!
I laughed at him and walked out.
They called me the next day and met my price.
Good luck in your negotiation but I do agree with others- dealer
location AND reputation are worth something.