Nothing except general wear and tear.
This is an excellent car. I haven't had any problems with it despite the intensive usage.
As far as comfort is concerned it is excellent, the electrically adjustable and heated leather seats are incredible and the self-levelling suspension is a delight.
The only things that let this car down are the performance and the automatic gearbox. Gear changes are not completely smooth. In economy mode, it is slower than a Ford KA, put it into sports mode and watch the fuel gauge go to empty within a few minutes!
The car is fine at very high speeds, put the cruise control on at almost any speed and it will give a smooth and quiet ride; it's just the acceleration that is the problem.
I have a 2.3 - the acceleration is strong and outperforms many others in it's class. Have you checked that the MAFF is clean, and that the catalyser is not broken in the exhaust pipe; two things which can lower the performance?
The problem with the Scorpio is that it is so smooth you can often be driving it with a problem and not know this.
If it's a dohc then check the fuel cut off loom.