Yes there is something called bump steer. With the frame mounted rack, the tie rods can cause a strange and unwanted steering effect should one side hit a bump and move the suspension that the other side doesn't. The change in suspension travel in effect, shortens the distance from the rack to one wheel and lengthens the distance to the other wheel. This turns the wheels without turning the steering wheel. Very bad news. For it to not have a bump steer, you would need to attach the rack to the axle, so the distance between the tie rods and the rack remains consistent as the suspension travels, but then you would need a slip joint in the linkage from the column to the rack to adapt the column to suspension changes. Such a thing does not exist that works well long term. Column stuff is just not designed to shorten and lengthen constantly as it would have to do as the suspension works. Sorry, Gene