Hi all, New to the forum here, learned a lot of good info for my BMW E90 325i here, but after some searching I could not find an answer for this particular question that's not "just buy top tier fuel". Well I wish I could but it's not available in my country, I used to live in the states and Chevron/Shell gas worked great for my B5 Passat, so I am now looking for a way to make my own "top-tier fuel" with maintenance dose fuel additives, can that be done? A little more info on the fuel here, they did introduce a new fuel standard relatively recently which is now 10ppm sulfur content (same as euro 5 I believe), I did service my fuel tank due to some unrelated issue and the tank looked clean, no deposits, gunk, etc. So my guess is the fuel here is of good quality but has little to none detergents added. Right now I am just using Techron every 5,000km/3,000mi , it works but I just fear that's not enough. My parents' F11 530i which receives less care and sees mostly in town slow driving needed new spark plugs in only 30k km / 18k mi covered in carbon, I try to pour a bottle of Techron in it every 10,000km as I go back home. Also a side note on intake deposits, when I removed my intake manifold to replace my starter, the intake valves looked clean just after one tank of Techron, but after spraying some carb cleaner into the intake manifold, what came out was dark brown colored and looks gross, should I use Amsoil Power Foam like many recommends on the forum?