I've always told customers that the hard part is finding the right vehicle, and the numbers will fall into place. Which is really just another way that I know to bypass that actual question of a customer trying to negotiate a discount on any given vehicle.
I've been in the car business for over 8 years straight now , and I'm still going at it. In my experience the easiest, and best way to get your best deal on a vehicle is pretty easy...
No matter what kind of car you're looking at...all you have to do is find a comparable model on-line with the lowest price. Call that dealer and start negotiating a deal on that vehicle and your trade-in too. Then take that same information, (or ammunition is what I like to call it) to your local dealer that has the car right there in front of you that you can see, touch, and actually test drive. I would even print the info out on the other vehicle that I found 4 states away to have with me.
Then you just simply explain to the salesman or sales manager that this is simply a business decision and it would not make since to pay more for a vehicle that you can get down the road for less. Most of all during this negotiation process try to be nice to the sales consultant and the sales manager. I've found that if the customer is nice and not a jerk about it that in the end we will go on ahead and match the other dealers deal...when normally we won't if the customer is being mean to us.
State your demands, and tell the sales team that it's strictly business and in the back of our minds as car guys we understand. If they say they cannot do it thank them for their time and leave....9 out of 10 times they will call you and do the deal...especially if they like you, but if it's someone that I hated talking to then I (the salesman) will not call them back.
Believe me I always hate it when a customer comes in with this type of information...and it really doesn't happen very often...so do a little bit of internet research and good luck on your new car!
Click here if you would like to see more of my vehicle buying tips: http://www.millionairesalesconsultant.blogspot.com