I just put on my new adjustable sway bar and I have it set at 19mm with otherwise stock suspension. Last night I was playing and got into a nice slide where my rear was coming around slightly faster than my front. Because of the road I also had to brake as I was sliding through the exit of the corner. I did have to counter steer just a little bit so keep things resonably straight but the car was also very much in control. If you are confident in you driving skills or don't push the car at all then the 18mm should be fine. Personally, I loved the control I had last night. Hope this helps.