This is my approach to main Dealers.
I always buy from a main dealer with a good reputation, and try to maximise the future power I will have in the relationship.
To this effect I have found smaller independant dealerships outside the main dealer franchise system to be both better to deal with and yet themselves more vulnerable in a confict situation.
IMHO, The vulnerability is in adverse publicity, particularly in the local press.
I always present to them as friendly and get to know all the staff and techs by first name.
I like them to use my first name and get away from being called Mr.
I have found reasonability if the car has faults to be key.
To be honest this approach has worked wonders with things being done for free even outside the warranty.
IMHO, being angry in the showroom is a non starter, it may get a result but the future relationship is ruined.
You are also on their territory and they have witnesses if anger takes you into slander territory.
IMHO if *persistant* reasonableness does not bring results, as the LAST RESORT a phone call going for the main vulnerability to a Dealership secretary is the way to go.
I believe in giving them time to think, and that a direct confrontation with the service manager or principal is at this stage best avoided ( of course having discussed with them both extensively before this stage is reached)
In this situation I believe a customer has much power over a supplying dealer and of course there are are human inerest stories ( of how you have suffered because of the car or feel like parking it outside the dealership with a board on a roof rack. "I AM NOT HAPPY WITH THIS FIAT !" the local press love so much. ( care of course with the potential legal aspects of this)
IMHO It would be a brave Dealer who risked adverse publicity, after all, some of them even
donate to charities on their website so revealing how IMAGE is so important to their business.