Now, if acetone hurts car paint and your skin, why would it be better for your engine as he stated? Using acetone can result in higher wear on rubber fuel components such as lines, hoses, and seals. Does it really work so well that the money you saved on gas from acetone will purchase you a new injection pump? I'm not saying it doesn't work, but I'm not going to try it.
Also, it appears this guy took mileage figures at only three fillups to show his "changes". The only way you can get good figures is to run about 12 tanks of fuel before any modifications are made and average them, 12 tanks of fuel during the modification process (ie: lighter loads, acetone, fuel addtives, etc...) and average them, then, stop and go back to your normal method of driving and record the mileage figures between those 12 tanks and average them out. Compare all three averages to see if there is any difference, and take into account things like the percentage of city or highway driving you did, the ambient temperature, if you used a/c or not, all of those things affect fuel mileage.
Then, there's the issue of stopping the engine when you'll be stopped at a light for more than 30 sec. Doing such will put more wear on your engine. Starting and stopping the engine frequently isn't very good. That's why cars that are primarily highway driven (I'm talking about about over 100 miles a day at speeds of consistently over 65 mph) tend to last longer than city driven cars.
