I don't know the specs on different years and models, but GDI (Gasoline Direct Injection) engines where the fuel mix doesn't cross the intake valve are the most important to do intake cleaning on. A big part of the problem is that the Positive Crankcase Ventilation system puts the vapors from the crankcase into the intake manifold so that it is drawn into the engine when the intake valve is open and is burned. Over time the debris in the vapor builds up on the intake valve, where it carbonizes from the engine heat had builds up to where it eventually will cause problems. Indirect injection, like throttle body or multi-port, injects before the intake valve, so the fuel mix tend to wash the intake valve, so there's little or no buildup. I bought my 2012 Base Soul to tow behind our motorhome, and it had low mileage, had been well maintained (even came with the maintenance records), but nothing showed whether the intake had ever been cleaned, so I bought the chemical kit and did the cleaning myself, hoping that it didn't have enough buildup that it needed mechanical cleaning. I'm retired now but the shop I worked in did a lot of VWs, which had big problems with the buildup in their GDIs, and we did walnut shell blasting when needed, so I had a plan B if needed. On engine teardowns, the oil control rings on the pistons often carbon up too, but that seems to happen after the intake valve is already pretty crusted up, and chemical cleaning often will get rid of problems there, too. All you do it inject the chemical into the intake until the can is empty, then shut the engine down for a set time (I tend to add 30 minutes or so, so that crud in the rings can loosen up better) and then you take it for a drive to flush out the crud. Man did mine burn a bunch of crud out. And I felt like I was driving a new car. I also added a fuel additive to the tank, plus did an oil and filter change. I was really surprised by how much more power the car had, plus my fuel mileage has improved. This picture shows the simple setup. You pull the intake hose and then insert the yellow hook shaped tube (note red arrow), put the intake hose back on over the yellow tubem put the correct size orifice in the hose from the can, then press the valve on top of the can and let the foam inject with the engine running. Easy.