I'm in the same boat as you, except I *wish* mine had an MBZ battery.

Yesterday, I looked at the battery in my 'new' '98, and it's a "Carquest" brand. And the vent tube is NOT hooked up, just a nice little empty grommet in the floor. I'm going to fix that today.

I don't know which of the very few *actual* manufacturers (Exide, Johnson Controls, Deka,) makes Carquest batteries, nor how good or bad they are.

As for the actual MBZ batteries, they are GREAT and tend to last a LONG time. Especially when they are in the relatively non-hostile environment of the trunk or under the back seat, where they are not exposed to the under hood heat.

__________________
Current rolling stock:
2001 E55 183,000+ Newest member of the fleet.
2002 E320 83,000 - The "cream-puff"!
1992 500E 217,000+
1995 E300D 412,000+
1998 E300D 155,000+
2001 E320 227,000+
2001 E320 Wagon, 177,000+

Prior MBZ’s:
1952 220 Cab A
1966 300SE
1971 280SE
1973 350SLC (euro)
1980 450SLC
1980 450SLC (#2)
1978 450SLC 5.0
1984 300D ~243,000 & fondly remembered
1993 500E - sorely missed.
1975 VW Scirocco w/ slightly de-tuned Super-Vee engine - Sold after 30+ years.