Vw has 15k/12 month intervals too, they can do this due to the high quality of oil.
A crafter on the other hand has 30k/12 month intervals as it has the same oil but 9L of it.
We get cars in which go 20-25k between services and never have had a problem with them.
So if you intend on leaving your 86 standerd, as in no major mods like turbos, go to Toyota and get the genuine oil for it. Toyota and Subaru would have invested thousands of dollars to manufacture the perfect oil for it. Don't let anybody mislead you and say its shit.