I have not checked the age of my battery yet in my E70, but I doubt it is brand new. I do have a more expensive larger capacity Group 31 NorthStar battery I took out of my E38 when it quit. It has a considerable higher amp hour rating and capacity then the group 94r that is in the car currently. I am pretty sure it will fit in the space. If I was going to just let one set around and not be used, I would prefer it to not be the $400 NorthStar battery. I know you have to register the new battery, but is there any issue with the electrical system in this car using a battery with more capacity? thanks