[Dominik]

For the half shaft it's diameter what counts. But your shocks get in the way soon. My buddy twisted the XJ half shafts often until he used some that are dimensioned similar to Corvette shafts.

His car is much less powerful than yours (10.6s E.T.)

My car had more torque, but I ran street tires - occasionally Hoosier Street TDs on public roads, never on real drag strips. Mine was also very light which helped (920kg).

Look what CAN-Am cars use. Amazingly thin control arms and reasonable diameter half shafts. I am not near one to measure.

Good luck!