For filters, either WIX or NAPA Gold (basically same filter.) I typically buy filters on Amazon in six-packs as Amazon Prine is good prices, free shipping, and two-day service to my front porch. No additives as premium oils have all of the necessary additives in them. (The exception may be zinc, but that a different discussion.) Thickness-wise 10-30 oil, is 10-30 oil regardless of whether its petroleum-based, semi-synthetic or full synthetic. The reputation synthetic has for leaks is totally unjustified. Seals and gaskets create leaks, oil doesn't. Since synthetic oil is man-made from scratch, the oil molecules all of uniform size, meaning there is less space between the oil molecules, whereas petroleum-based oil molecules are all different in size because the raw product comes from the earth or ocean-bed meaning there is more space between the oil molecules. During the life of the oil in your engine, those spaces between the oil molecules are going to fill up with dirt and debris that gets past the filter because it is too small for the filter to catch. The longer the oil stays in the engine, the more dirt and debris it picks up. (For clarification, these particles are so small in and of themselves that they typically don't damage an engine, but even the best full-flow oil filters trap and hold essentially all particles larger than 25 microns (a human hair is roughly 70 microns in diameter.) So, it's easy to see that with a petroleum-based oil, with larger spaces between the oil molecules, more dirt and debris is present which actually keeps the oil from leaking past worn seals and gaskets. It's not thicker (viscosity-wise) oil, it's just occupying more space. So, another way of putting it as opposed to saying that synthetic oil causes leaks, is that synthetic oil identifies work seals and gaskets. But as far as synthetic oil being a negative, it's one of the most positive inventions in the automotive engine since we replaced babbited rods with rod-bearings in the 50's. My choice is Mobile One and have used it for too many years to mention. I typically get 300K miles on my drivers with Mobile One full synthetic and Wix filters, changing oil and filter every 5000 miles. I change the oil/filter in my El Camino (300HP 350) twice a year as it will see less than 1000 miles per year, and only in the summer. Hope that helps..