I have an unusual circumstance. I'm looking at a 2007 4S. The Vin is coming up as an S. The floorboards say 4S and the name plate on the rear has been changed to say 911. The owner seems legit, but it feels weird. How can I tell if it's a 4S. He claims the vin is an error.

 

Well, you can get under the car enough to see if there is: a) drive shaft up the center tunnel and b) a differential and driveshafts for the front wheels.

If you have looked at a number of 997s, you can compared the space in the trunk: the differential and all takes up a lot of space that is otherwise there.