I have played the Fianchetto KID with both colours, albeit not as a main weapon of choice. The detail required to learn it with either colour depends on your level. If you are under 2100, then you should be able to play it solely by knowing the key ideas, themes and manoeuvres, along with awareness of the main traps. However, above this level a proper knowledge of the theory is required. 

With all due respect to Jangjava, I wouldn't spend my time studying his book, as it resembles a database dump sprinkled with 'b212', '+=', 'black should play this...(no further comment)' and the like. I must confess that I don't own the book, but I have looked at it and also seen a couple of reviews confirming this. 

Some strong GM's whose games in the Fianchetto KID are worth studying are (in alphabetical order): Akopian (hasn't lost a single game with it yet), Andersson, Arkell, Bu Xiangzhi, Dautov, Georgiev (these last two have played a dozen games each in this line), Granda Zuniga, Huebner, Ivanchuk (most of his games in this line are rapid time-controls, but still instructive), Jussupow (beat 2600's with it in the early 1990s), Karpov (definitely the main expert in this line in the 1990s), Kortschnoj (he has some creative ideas), Nikolic (this GM is a KID-murderer; +9 =4 -0), Lajos Portisch, Sargissian (he knows his openings well), Tregubov, Wojtkiewicz (to answer Bibs's question).

As I have decided to continue to build my 1.d4 repertoire with fianchetto systems (as much as possible). Now I am studying the Fianchetto Kings Indian. But I am impressed by its richness and complexity.  So the problem I have is to form a repertoire against the KID with this opening. I wont wait for Avrukhs second volume. 

So my question is : Anyone here playing the Fianchetto against the KID ?  Is it possible to play it mostly by learning the ideas of the opening or do you have to devote your life to it ? .....like playing the open sicilian ? Jangjavas book just scares me off.