I went to CarQuest today. I was going to give Royal Purple a try. Well two years ago RP was $4.99 a quart. Today it was $5.63 a quart. So I passed on RP. Instead I ended up walking out with old school Amsoil 10W30. They now cary Amsoil as well so I can again get it localy. I think it was $5.13 a quart. Now my Napa also carry's Amsoil but they only cary the Series 2000 for some reason? This oil will be used in the old buick. I could not belive that RP would demand a higher premium the a time tested oil like Amsoil!!!