You will also need to also change the switch on the column from a two speed switch to a pulse type wiper switch. If you do not have a tilt column you will have to change over to a tilt column to get the correct switch to go with the pulse type cover on the wiper motor.
At least that is what I had to do with my GN with the two speed wipers and non tilt column to change over. Was worth it avoiding switching the wipers on and off, in the misty type rain showers.
By the way any pulse type cover from a mid 80 G-Body wiper motor will work on your wiper motor, it does not have to come from a turbo Regal