[Blue)(Fusion]

I really don't know what dealerships do when they go to sell a used vehicle. I suspect they'd try to spend as little as possible and go with the "if it's within spec and works, don't fix it" mentality. I could be wrong, though.

You can always pull plugs and check them for proper gap, check the plug wires, filters, and fluids yourself.

dfordski also has a point about the timing. Although you don't have to advance the timing, you should determine whether it is set appropriately. If it's retarded too much, it will kill your mileage and performance. The more advanced it is the more power you extract from the fuel. There's only so far you can advance though before it starts pinging.