Ask for 40k and make them think you are absolutely prepared to buy if they give that to you. It's helpful to actually be prepared as well.
List the reasons stated in here:
Originally Posted by Bavarian Motorist
1 They are (probably) paying for floor planning (meaning interest to the manufacturer) on 2 a car that is probably not extremely desirable given its mileage, despite being "new". Definitely not as desirable as a barely-touched new car, yet that's the price you're being offered at $48k, IMO.
3 With the new model year rolling in, the car is going to depreciate even faster because it will be a 2 year old car. 4 They have no choice but to clear it out for new inventory anyhow.
Do not want the car more than they want to sell it to you. Be prepared to walk out on it if they say no. They might let you go or they might try to work with you.
You have to have the mindset of, "I don't REALLY want or need this car, but if you're willing to give me a really good deal..."
Anyways, hope I helped.