My t-4 had the FI on it and I never considered swapping it out.
Maintaince is more expensive than carbs. Just grab a PP cataloge and price out the bits (yike), but........
Your reasale value will go right down the tubes. Originality will become even more important as time passes. How many guys have you seen (on the net) looking to buy a hotrodded T-4, 914?
Those willing to pay big bucks want originality (except racers, of course).
Carbs stink.....no other way to put it. If you like the smell of gas, this isn't a problem. Most of the "kits" are not well engineered.
Gas milage heads south, also.
There is a learning curve to each system. Figure a year to get used to tuning the carbs
I grew up with carbs, but the Webers took some learnin'.
FI is basicly tracking down a failed part in the system and replacing it....which can be challenging , also. ...ask DD :-)
Your "bug" mechanic prolly knows zip about your FI system. It's up to you to become an expert
or find another wrench.