I have fixed the problem !
For the raising problem, i have making a dummy (extra_1,extra_2,extra_3, ect ...) scaled 0,04 for X-Y-Z and i have placed the dummy on the leds .
For the handling I have place the car as "police2" and the car work perfectly ! I have compare the two handlings and the diferrence is the center of mass, police=-0.16 and police2 = -0.27.
Thank all for your help !