My 4.7HO has plenty of miles on it (over 100,000 miles).
Here is an example of perfectly clean and refurbished stock injectors vs. different Bosch injectors:
The condition of the stock injectors in that video would give you their best possible performance. Even with that, you can see how poorly the injectors atomize the fuel. It is more like a squirt gun shooting fuel into the cylinder head.
It seems that if you could atomize the fuel better, you should get better fuel mileage as well as maybe even better performance. The question is if $300 for a set of 8 is worth it. Maybe if you were looking at replacing the injectors anyway.