Technically, the difficulty is 1 in 10 to do it.
There are some things that you should have control over.
With or without carb heater, and OE vs NE.
OE vs NE is a microscopic difference, the most important is a different cable connection to the rear heater.
Carb heater has a different flywheel and generator, I myself have not studied with or without carb heater, so I do not know the resistance difference between the two generators.
Most 346 xpg's in Norway are without carb heater.
Price-wise part for part, it is the flywheel and generator that ruins the project, if you are going to come out reasonably economically on it, used flywheel & generator is the way to go.
The generator itself is similar between 562, 560, 550, 357, 346, only the length of the cable and the cable lug are different.
There is also a small cable protection, # 504043501, which is from the tank to the handle, very nice to buy when you first do the conversion.
A weakness all generators have, from 2xx to 5xx is the mounting of the wire inside the generator, this certainly applies to Stihl as no one has gone far to be unique...It is easy to fix though.
Also be aware that Husqvarna has started phasing out 3xx parts.