The key is a combination of rack length that fita the length of the lower control arms for zero bumpsteer and also places the tie rod end correctly for ackerman for a street car. For a race car(mine) zero ackerman saved my keester three times and allowed me to correct quickly when i blew an oil system gasket at 150 mph , got sideways at 125 mph on a slick track, and again at 135 mph when i hit a dip in the track with the brakes on hard.. I don't recall seeing many successfully recovering from being out of shape as bad as i was. Credit the fact that the front wheels stayed dead parallel at all steering angles so the front end didn't push me into a spinout.