153 skid will bolt right on to the 162 rails, i just did mine. I used a cat tunnel extension, cheap and easy. I just added some extra heater hose to the cooler rails to join up to the rear cooler since it gets set back further. I would also suggest to buy the longer rear bumper, I tried the shorter bumper but it doesn't reach up to the foot boards and creates a weak spot in the tunnel, you could end up with a nice wrinkle like I have.
The only difference in the rear skid between a 153 and 162 is the length of the rails. You can swap new 162 rails in, or get extensions. Either method will work.