I just did the screw-through-the-bellcrank mod after finally stripping the crank on the used car I bought. Looking at the new pieces, I noticed that the crank arm and bellcrank are keyed so that they only fit together one way. This, I think, is part of the reason why this part eventually failed; I run the inner ackerman holes on the bellcrank, which makes it so that when the steering is set straight ahead, the white plastic arm cannot be perfectly perpendicular to the centerline of the chassis because the keying will only allow the arm to be perpendicular when the outer ackerman holes in the crank are used (the standard setup). Basically, in trying to get that arm aligned, I damaged the splines on the bellcrank by not noticing that they were keyed, which I think may be happening to others who may not have the manual for the car or just haven't noticed the flat spots on the bellcrank and arm.
Moral: the white arm only goes on the bellcrank one way
