The car really did go from being sluggish to acceleration and speed like when I first bought it. However, at the same time, I was getting a 30K service (also, rotors, oxygen sensor, etc.) which might have also improved the performance somewhat. My gut feeling is that the cleaning of the combustiion chambers did improve the power that the car had. Would like to have a Master Mechanic weigh in on the matter of the effects of cleaning out combustion chambers after the car has 80,000 or more miles on it.