http://www.kbb.com/kbb/UsedCars/2010_Ford_Mustang.aspx

Mine had a sticker of 36,540.
(Mods so far: ~2,500)

Trade in (between exc. and good): 25,400
Private party sell: 28,950
Suggested Retail is 31,800

Some options on KBB aren't listed tho: HIDs, security package, remote start, shaker 1000, reverse cam, track pack, etc... quite a lot actually lol

So, for whatever it's worth, many dealers use KBB over the others so just something to take note of.

 

Dealers that are competitive with remarketing do not even use KBB. They are either using BBCI, Galves, or most typically actual auction results. Wish they did though!

 

The Dealers around here use auction sales to gauge value. It's also summer so demand is up. So value goes up a bit.

 

I used two of the largest dealers in the metro San Antonio area and they both used KBB. For what it's worth...

 

Maybe it's different down south. It seems to me (being on the outside, but a very frequent car buyer) that dealers would lose money using KBB consumer guides for trade values. With auction, they always know approximately what they can get running the vehicle through the lane instead of selling it on the lot. I've worked with dealers that have the KBB calculator on their site to attract buyers, but use auction values to actually appraise the trade. But every place is different

 

Most use auction values and work from there.
Good example is the 2007 Stang I am getting this week.
https://themustangsource.com/showthread.php?t=483883
They paid less than KBB because I am buying it for KBB trade-in value.

 

A dealer will look at all sources, but will mostly rely on auction reports. If KBB is in line with auction reports, they will tell you they use KBB. Whatever makes them look better to the consumer to gain their trust. No dealer in their right mind would rely on one source as there are way too many variables between all of them.