We had a close call when we weren't able to destination charge with our X60D this winter in a rural area with 10 degree temps. But, as the temps warm up it seems to be much easier to achieve close to rated range. I think the key is really driving gently, not only reducing your top speed but also really resist the urge to accelerate quickly, especially up hills. I've found the autopilot is not that good at this, so you may have to take over if there are frequent hills.
Lastly, the S60 owners were lucky to have their upgrade price reduced to 2K, but us X60 owners did get a 3K reduction to 6.5K. Common wisdom around here is that it's still a bad deal, but honestly I will consider it before my next road-trip as it's something I'm going to want to do eventually for a little more breathing room on legs of the trip where we're able to charge to 100%, especially trips not involving superchargers that approach the 200-mile range limit. S owners have a little more efficiency, I think with the X being a little less efficient the extra range boost is more valuable.