I wouldn't negotiate price until I stepped in the door because to my way of thinking it shows a true scene of commitment on your side. As well you've already asked them to hold the unit until you get there. Now will they hold it just because an anonymous voice asked them to? Welllllllllll maybe yes, maybe no, LOL.
Another way of saying this is: talk is cheap.
Finally, you have no idea of what the unit looks like after it's travel from factory to dealership.
JMHO and how I negotiate. Others might have a different way that's just as viable.
HTH