Welcome to FTE. It all depends on how well the truck has been taken care of. If it's had proper maintenance, then for not much money and the help of FTE, you should be able to take care of any issues that come up yourself.
Here's a few things to look at when buying a 7.3
http://www.ford-trucks.com/forums/52...questions.html
The most important in my mind being the plastic tube that goes from the air filter back to the turbo. If you find lots of dust in there, be cautious. If it's clean in there, the biggest hurdle is out of the way.