My Walmart has Havoline conventional for $13.24 for 5 quarts... Making it only 50 cents more than supertech. I can't find a current pds that specifies Wss-m29c-929 that my car recommends though. I've heard great things about Havoline, and this stuff is dirt cheap. Any harm in using it? How important is this ford spec as most conventional gf5 oils meet it?