I changed my oil today and I usually use Walmart SuperTech synthetic, however when I checked the bottle, there was no indication that it was made by Warren. Usually there's a WPP stamp or something on the bottle, but there was nothing on the bottles on the shelf today. Rather than taking any chances, I picked up a 5 quart jug of Quaker State synthetic for $2 more. I change my oil every 5000 miles so it probably doesn't make much difference, but does anyone know if Walmart changes suppliers for SuperTech?

Yup.