Short answer, not worth it.
you won't find any electric fans that move anywhere near as much air as the stock fan. Stock fan is in excess of 10k cfm air moved, and most electric are in the 2k cfm range, so you're talking a lot of fans and having to have room for all of them.
I believe it's been said that the stock fan requires about 10hp to operate.
There is one guy that did it and seems to be happy with it, but he separated every single item out in the cooling stack and has electric fans on each system, so 4 or 5 different ones spread out all over the engine compartment.
The most useful fan mod seems to be going to a civilian style viscous type that eliminated the cadillac valve and related system. Draws less power, and keeps the engine at a more steady temp.