My own experience: I have an 06 F350 with 6.0.
Currently showing 112k miles. Exhibiting a bit of stiction on the injectors, rev-x is on order to take care of that. Blew a HPOP seal at 94k miles, fixed under warranty. Otherwise, it has been bulletproof. A friend has an 02 F250 with 7.3. He has lost the crank position sensor (common problem with them), otherwise the only problem he has is getting left behind by me.
If you want to make a 6.0 very reliable, do these things:
1. Buy an 05 or later 6.0
2. change to an ELC coolant (stock ford coolant can clog up the EGR and oil coolers), and maybe put on a coolant filter.
3. Regular oil changes, preferably with synthetic (I use Rotella T6 in winter, T5 in summer)
4. Get an Edge Insight gauge package, keep an eye on the water and oil temps.
5. Leave the engine alone.
You do not need to install head studs, unless you want to add power. The studs may cost $500, but it's at least $3k in labor to get them installed. Not a job you can do in your back yard on a weekend, the easiest way to do this is to pull the cab off.
Removing the EGR: mine is still in place, hasn't caused any problems. If it ain't broke, don't fix it. Then again, I changed coolant early on, flushed it once six months after the change, and the Insight box tells me if there's an imbalance between oil temp and water temp - a sign the oil cooler is clogged. So far, so good.
Adding more power - The 6.0 is a lot touchier than a Cummins for more power. Do your homework before going this route, it's expensive to do it right, and very expensive if you do it wrong. The penalty for error is blown head gaskets, and that's $4k.
The problem you run into with the 7.3 is: most of them are older, most have a lot of miles on them. It's a good engine, but even good engines develop problems with enough miles. And the transmission isn't quite as solid as the 6.0's 5R110. Tranny problems can cost serious money too, but if you've owned Dodge, you may already know that.