Hilary more than likely will not hit SoCal full force as a Cat 3-4 or even a Cat 1, because it will be going into much cooler waters prior to final landfall. It will weaken considerably from its present state prior to rolling through. There will be tropical storm force winds and the rains are definitely a real threat, but it's not going to be like Laura pounding Lake Charles in 2010.
It'll be bad enough with the flooding, though.