i did it to my two 9s. there is a 40mm nut you need to loosen then nip back up on the steering rack. the tighter you go the stiffer the steering wheel. you cant miss it. look under the car and trace the steering rack its under the drivers side foot-well. if that does not solve the problem look at your tie rod ends, steering rods or your steering coupling. just tug your steering rods to see if they have any play. its recommended for steering racks to be tightened every so often.
hope this helps