i have modified the mini slider steering to accept a normal size servo. one car with a "Rack" and another without a rack(from custom works) ridding the car of the terrible slop of the stock steering.
i'll try to get pics soon. but it's really simple. removing the stock steering completely. i fab a small bar shape mount to fit on one end of servo. drill two holes in servo saver. using kyosho eye ends that go to the servo rod i change both ends of the tie rod, so you can use a flathead screw instead of the ball end. mount the servo vertically with the bar mount attached to the front bulkhead screws. you may have to trim bulkhead a little, where the tie rods go into the center area.
i had to learn to drive the cars all over again as the steering was very precise and quick. having a transmitter that can adjust to quickness and sensitivity really helped also.