I also use the O'Reilly/Autozone/Advanced Auto "Miata" batteries with no issue. I tried a Westco once, I deep cycled it twice in two weeks and killed it. I was pretty pissed about that. The one I bought at the autoparts store was identical to it, cheaper even, so I moved on. I know Stevan (Rogue) swears by the sealed MAT(?) batteries though.