I always here that too, but I also know that "back in the day" battery cases were porous, which is why you couldn't leave them on concrete, and that isn't the case these days.
I just can't see how Porsche could put the battery in the passenger compartment if it was a problem, but we're digressing from my question....
Would relocating the battery to the rear make enough of a difference in this application to matter?
I've has horrid experience with Optima batteries btw. Both XJ's have them and I'm forever having to jump start thing things. This wasn't the problem prior to the Optimas...