I've never paid much attention to Gulf Western Oil, but it's an Aussie own company that has been around for just over 30 year. Their Premium Gold 15W-40Â just caught my eye, it's a semi-synthetic that is on sale right now at SCA at just under $22 for 5L API SN-Plus, SN/CF KV100 = 14.9 cSt TBN = 6.5 (ASTM D2896) SA = 1.2 % (ASTM D874) It's the first SN-Plus 15W40 that I know of. Also it seems to have a lowish TBN for a rather high Sulphated Ash (SAPS) level. Maybe elevated ZDDP ?? Does anybody know anything else or have any experience with this company or oil ?