I am getting stuff around to do an ATF drain and fill on my wife's Malibu. I'll be doing my Equinox this spring. I will be using either Amsoil or Redline Dex6 for both vehicles. To get the majority of old fluid out I will be doing an initial drain and fill, drive it for a few days then a second drain and fill. My question is, is there any real difference in quality or durability between the two products? Which would you choose? BTW, just for giggles I will do a UOA on the factory fluids.