OK thank you Serum for the diff, you'are right, it's a Spyder diffs, and it' bulletproof, but you not tell me why you said that clutchbell is unecesary on a brushless....
The main reason why i want a clutchbell, is when i land a big jump, i want that the clutch (and not the motor) take the big "spin" of the center diff when the wheel touch the ground.
When you hit the brake in the air to "nose down" the buggy, the wheel stop to turn, and when the buggy hit the ground, the wheel re-start to spin and give a big "hit" to the motor, so with a clutchbell, you eliminate this problems.

My goal is to make it very reliable.
And if i don't like the clutchbell system, i'll simply re-instal the right motor mount for the buggy and return to a standard pinion/spur setup.
And more easy, the tekno Electri-clutch have a 5mm shaft where the clutchbell bearing, so i'll can leave this in place and simply put the standard pinion on the tekno elektri-clutch adapter.