So I've only had my Duramax for a week now but I've been shopping around for things like DEF so I know exactly where I'm going to get it when the time comes to add more. I was at Walmart and noticed their Super Tech brand DEF is only $7.88 for 2.5 gallons. Which is a good bit cheaper than the name brands. I always try to use name brand stuff when it comes to maintaining my vehicles but is it necessary when it comes to DEF? It states on the jug that it meets requirements for all SCR vehicles and has the API stamp that the Duramax manual states to look for. I'm thinking it will be fine since it's just getting sprayed into the exhaust and meets standards. Has anyone tried it?