I actually snapped a few pics anyway for a visual reference so that I don't have any trouble during reassembly so it was no big deal really. This vehicle was a recent purchase for pulling a camper and it was used as a tow rig before so I assumed it would be pretty nasty in there. Regarding EGR functions I feel that 1project2many has the best theory about EGR and gas mileage. Every engine configuration reacts differently to changes so it would only make sense that EGR operation would be no different. If you take a moment to remember the theory of how EGR is supposed to work it helps to understand when it may be helpful and when not. The function of EGR is a crude way of reducing engine displacement and fuel consumption by pumping a metered amount of inert exhaust gasses into the cylinders under light engine loads when the demand for power is low. Still, different engines are going to respond to when the EGR is enabled and such differently. I personally have always disabled EGR functions on my vehicles for simplicity, but it can be useful. As for my cleaner testing, the cleaners that I am testing are eagle one chrome wheel cleaner and eagle one mag wheel cleaner. I have worked with oven cleaner before too and it is pretty decent too. It is not just the actual brand names that I am looking into rather it is the base chemicals and the combinations. Everybody knows that muriatic acid is excellent for stripping iron and steel, but it literally eats aluminum. Phosphoric acid works on both, but has limitations. Sulphuric acid also works in small quantities. Sodium hydroxide is an excellent cleaning agent and is the main ingredient in oven cleaners as well as aqueous parts washer solutions. All of these chemicals are readily available and they are also the main ingredients in many cleaners out there. The problem is that these over-the-counter cleaners are pretty expensive by volume. My testing is for the purpose of finding which cleaner I like and referencing the main ingredients and percentages listed on their MSDS sheets and then attempting to mix up my own concoction using readily available and inexpensive concentrated solutions of the chemicals.