"We had 5 cars cleaned and each one seemed to show improvement in power and economy. The C6 which also required a new fuel filter is delivering 34.9 MPG which is about 3-4 more miles per gallon than before. It also seems to have more acceleration. The car has 78,000 miles. My Mercedes S500 2002 with 120,000 miles seems to run better as well. We are still evluating, but the preliminary results seems positive. The good part about this is that the treatment does not require any disassembly of the engine. If possible, I would suggest that you have them demonstrate by treating an older car where you can then take some of the parts out for inspection."