I put platinum 4s in my old subaru AWD turbo, worked fine. But I used NKG on my conquest works pretty good.

BMW's...high maintenence? nooooooo....what BMW's you looking at? bmw's are average 300-500kmi motors without having to touch internals. just general maintenence man. I can understand an older 3 series and 5series but when you get past 89 should be golden for a long time on vitals.
jeff