Thanks for those first comments and advices!
So left clamping hub will fit the original L3 rear axle BUT Diff plate are later if I understood well! I did notice some difference with the drawing, the L3 get Round diff rings as the L4 get D-shape diff ring but haven't notice the larger diameter, thanks then!
For the thrust bearing, it's more regarding the state-of-art in machanics and perhaps some reduce maintenance in this area than other thing. A search give this message
http://www.rctech.net/forum/showpost...postcount=6011 with some explanation. Also found Mark Payne blog with some explanation, that help! I probably manufacture a part and buy a thrust bearing to the job!
I assume tires choice seems relevant! There is various manufacturers but color code will be almost the same?
If other advice, welcome they are!!