Modifying auto column for manual floor shift

There's a couple of good threads here on FABO showing how to modify the steering column collars to eliminate the shift indicator and the snout of the shift lever. I'm currently doing that on mine. Beats paying $160 for new collars! :)

When reassembling, I'd like to leave out parts that no longer have any function. I will probably keep the steering wheel ignition lock but there's no need for the Park interlock, or shift detent plate.The outer jacket is already shortened back to the firewall for header clearance and the shift arm is gone. Do I even need the inner tube, and the plastic bushings that align it, or can I get rid of them?