I saw a used 2006 Cayenne S with 45k miles for $14k.

Is this a good buy? All stock. No upgrade of the coolant pipes yet.

 

That's low miles.. I paid $9,200 for my 2005 Turbo with air suspension, adjustable shocks, Bose Audio, trailer hitch prep package, thermally insulated glass, and a few other things that came with it... Has 118,000 miles on it when I bought it.

If that's the standard V8, and has been well maintained (mine has two previous owners and for sure was a family rig as there are cosmetic wear on the interior). If that unit is pretty mint, I'd say maybe try to talk them down a bit, but seems right in the ballpark for sure from what I've seen on several different car listing sites.. These things are monsters..

What features does it have? The air ride adjustable suspension is super nice. Already took mine wheeling. The low range for moving slower is also nice...

 

You could go on CarGuru and put it in their market value estimator. Seems better than KBB for actual sold recently value.

 

What are the options? pasm? pcm? you can run the vin here.. https://vinanalytics.com/
I believe you can buy a 957S for that if oyu can find one... GTS can be had $15k and above depends on the mileage..