I've had really bad luck with Autozone batteries, both on MB any my more pedestrian cars. Out of three batteries purchased, two did not make through the first year of life. Don't know about the third - sold the car. Yes, they have a good warranty, but if you have to use it that often, I really don't want anything to do with the product.

I have an Optima orange top in my '87 wagon and it is fantastic. Never needs water, never leaks acid, spins that six cylinder diesel like crazy. Yeah, it cost ~$130, but any good battery was above a hundred. I've had enough bad experiences with 49 dollar batteries to have sworn off them. Ever try to jump start a diesel benz with a shorted battery? It's damn near impossible to get it going. Been there, done that, don't like it too much.