Can't speak for the AGM - but I'm 62 months into a Deka maint free part # 749/93 ca=1050 cca=850.

I've used just about everything else and have never gotten this duration out of a battery in my 126 MB.

Your Interstate has done amazingly well - 9 years - wow!

__________________
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"