Manual vs power rack and pinion
I would say steering effort is the only down side and that will be offset by the gear ratio in the rack which would bring you back to 4-5 turns lock to lock. Power Rack would probably be closer to 3 turns lock to lock with minimal effort.
Personally I have manual stock 24:1 in my dart and it is not a problem.
My dad always said "The parts you don't add don't cause you no problems" and "KISS" - Keep It Simple Stupid.
words to live by!