You need to take a close look at what you're going to use the bike for.
In my case, I have a 2014 SR with the 11.4kWh battery pack. My primary goal was to use the bike as a "power commuter". My daily commute is ~52 miles round-trip, mostly freeway speeds, and I always get home with 30-35% left, toward the higher end in the summer, toward the lower end in the winter. Any other riding I just manage, knowing how much range is available. If I want to cruise up to the mountains near me, no problem, I know how far I can go. I live about 20 miles from the beach in San Diego, so I can go cruise the beach, but not very far.
I find that I worry far less about running out of power now than I used to. I've actually run out of power twice; the first was on an extended ride to intentionally push the range of the bike, and the second was on Craig Vetter's mileage challenge July 4th of this year. The first time I had to push the bike maybe 200 yards to get home; the second time I had to stop for an hour and find an outlet to plug into to finish the ride. Both times I knew there was a possibility of running out of power, and probably as a result of knowing that, it was just no big deal. The first time I was grateful I only had to push 200 yards -- even I can do that with a bike this light. The second time I was just embarrassed I didn't make the finish -- at the turnaround point I had 52% remaining, and the return trip was mostly downhill instead of uphill, but I forgot to account for the ~5 mph onshore flow that made the bike think the trip out was at 60 mph and the trip back was at 70.
So I'd say that if your primary use for the bike is met without having the power tank, don't worry about it for now. You can manage the rest, or if you change your mind later, you can always add the extra capacity later.