There are sooooo many ways to save 40 lbs in any of my cars right now. If I decide to do that, I'll pick one of the ones that involves taking some stuff out for free as opposed to paying $500 more than my current battery. It's sort of like my co-worker, who's an avid bicyclist. When asked why he didn't have a carbon bike, he said that if he wanted to lose 10 lbs off his total vehicle weight, he should start with himself before spending on the bike.
I'm also really not sure how keyfob wireless jumpstarting works. Is there lightning flying between the two cars?
I'm with you and @kurinin, this is solving a problem that doesn't exist.