Hello everyone. I would like some advice regarding my vehicle. 1986 BMW 325ES. The car has between 150 - 200k miles (odometer has stopped at 149k, bought this way). The car currently has conventional 10w-40 in it. I would like to swap to synthetic from personal preference and experiences, but never attempted on a car with this many miles on it. The car doesn't smoke, exhaust appears clean and, according to previous owner, doesn't consume any oil between changes. Service manual for the car lists 10w-30 for my areas temps (GA). It is early fall here so I expect this oil change to last through the winter months where we will see temps usually between 30-50 average, maybe 15-35 on a worst case scenario. In addition to the proper viscosity issue, I am confused by the type of oils available to choose from. My preference is Mobil 1, again that's just from experience I'm open to suggestions. They offer a high mileage oil in addition to their standard synthetic. This would normally appear as a no-brainer, however the packaging comes into play. You see my parts stores are always typically running some type of sale where I can get the oil and filter for around 30 bucks. This comes as a 5 quart jug. However, the high mileage oil is only offered in quarts for 10 bucks a pop, plus the filter which effectively doubles the cost of the oil change. My question is why? And is the high mileage oil a sales gimmick or not? If not, is it worth twice as much as the normal synthetic? The manufacturers website isn't helpful in discerning the difference. Instead of a good breakdown of whats really different about them, it looks like a bunch of marketing guys put up a bunch of vague positive facts that confuse me. I've even plugged my car into their "what oil is right for your application" and it tells me 0w-40 synthetic, but doesn't ask me about my mileage which I find all the more confusing. The car will be driven by my wife, so I would say it will be typical city driving. Any help on this would be greatly appreciated, thanks for your time.