Been avoiding buying Amsoil products all these 36 years of driving (marketing...hype...price...mail ordering/$hipping...etc), but today I went to NAPA for some 75W-140 rear end oil. Much to my shock a) they stocked Amsoil b) double shock, it was LESS than M1 and competitively priced (about $15.XX/quart) with other gear oils. So, I'm going to put it in the Frontier (which already comes with syn as FF) and I'll report back if it "likes" it. (Believe it or not, I've read several posts on Nissan forums where the drivers could "feel" more power, smoother, etc.)