Patrick  
This book is very interesting , but do not forget the ones dedicated to JG52 at Deutch Brod and to Bf109G-10/U-4.  
You will find also really interesting information in them, espacailly on the differences between , Messerschmitt, Erla, and WNF produced Bf109G-10.  And good new information on Diana, Plant producing Bf 109G-10/-U4 in Czech rep. 
Eric