The pre wash does exactly as it says, takes a helluva lot of the crud off the car, makes for a much easier time with the shampoo side of things, must say I was pleasantly surprised with the actual car wash stuff, I was very sceptical but I'm sold on it. I will add that I am disabled and using this stuff I am able to wash the car, granted I can't do the wheels but that's what the kids are there for eh.
Overall I'm impressed with the bundle, will I buy again, absolutely I will.