I have washed mine with a power washer numerous times. The condensation (smoke) is fine. My belt was really squeaky one time because it was wet, it went away after a few minutes. That is just the water evaporating into the air due to the engine heat. The engine is constantly in the enviroments, using a pressure washer on it is fine.
Here are some tips for you:
*Cover the fuse box (if you feel its necessary) I don't
*Cover the intake (I just avoid it) A little water can get in there because there is a drain at the bottom before the intake portion.
*Spray the crap out of her! I spray everywhere!!!! You can spray a cleaner on prior to it for assistants.
*Let the car sit for 10 minutes or so after spraying to dry some of the water with the remaining engine heat.
*Let the engine run (idle) for 10 minutes or so to dry off the reamining water.
*I drive her very calm for a few hours to just make sure everything is gone.
This should get you cleaned up.