From rctech forum, I think this guy explains the matter perfectly (
http://www.rctech.net/forum/13410214-post8049.html)
I always felt the same about the 22's I had driven. They just were not aggressive in the corner and there wasn't a lot of feedback. You felt like you were guiding the car, not driving it. I never liked the stock ackerman, it is much too exaggerated and makes the cars steering feedback inconsistent. I held on to my XXX for a long time because I wasn't confident in the feel of the 22. When I finally made the change, I started comparing the two cars and steering geometry was the big difference.
My cure was to move the inner ball studs as far forward as possible on the rack. I have removed about half the thickness of the rack where the ball studs mount. This greatly improves the ackerman and makes the car have a lot more feel, especially mid corner. I removed enough material that I also had to remove roughly 3 threads from the end of the ball stud so it did not protrude and interfere with the slide for the rack. I also had to trim a little of the slide to clear the ball cup at extremes. When you look at the car directly above the front arms now, the tie rods are straight across instead of swept forward at the wheels. It has made a big change in the car and everybody that has driven it notices the difference in feel.
The bell crank steering should do the same thing, probably even better although I want to try just the spindles with my modified rack first. A lot of the ackerman comes from the angle away from 90 deg. that the steering tie rod ball stud is from the king pin. Closer to 90 = less ackerman and from what I can see, the new spindles have changed that relationship closer to 90.