The battery I'm removing from my Z (which will be replaced by the Braille) is a Diehard Gold Series. I have the receipt from 1999 when the previous owner had the Diehard installed. Frickin' 9 years ago! The Diehard is still going strong too. I'm replacing because of age, to clean up the engine bay, and to lose a few pounds. Hopefully the Braille will be a reliable battery, and I won't regret this decision. We'll see.