Difficulty: It depends on what route you take.
If you tried to swap the panel inside the housing, you might as well forget it. Apple doesn't even do that, they swap assemblies.
If you want to swap the entire assembly:
1. Removing the bottom cover
2. Remove the battery or disconnect battery cable
3. Remove AirPort/ Bluetooth flex cable
4. Remove AirPort/ Bluetooth card holder
5. Remove camera cable guide
6. Remove LVDS cable guide
7. Disconnect the display cable
8. Remove 6 Torx T6 screws
Do the reverse to put the new one in.
In regards to getting it swapped with a higher panel due to a defect, in theory it makes sense and there is no difference in the pricing of the parts (from a repair perspective). However, I don't think Apple would do this generally (for a number of reasons).