You don't want the 3.0 upgrade. You'd likely want this 3.5/4.0/whatever they're calling it.If mine still yields 135 miles after 137K I'd be happy. Hopefully they'll be a 3.0 battery by then.
What I find interesting is that from 122k to 137k the car didn't lose much range. Remember 135 ideal isn't real world 135, I would have to look back at the actual daily mileage the owner quoted to me, but the concern was that it wouldn't be a good fit for my needs.