am I going to be busting my kidneys on this bike if I buy one?
I weigh 210 lbs on a good day. I normally set my rear spring to setting 5 when solo and carrying no extra load. I bump it up to 6 or 7 depending upon how much is stuffed into my cases. I consider it max-stuffed when I carry a laptop, work tool bag, rain gear, lunch with a couple beverages, extra jacket and gloves, and some little stuff like maps and extra earplugs. With all this, position 7 has been fine for me. Granted, I'm not riding super-aggressive when I'm carrying this load.
Riding 2-up is another story, and feels like it needs more pre-load than position 7. But, it doesn't keep me from enjoying 2-up, and only bottom-out the suspension when I hit an occasional driveway transition or big bump a little too fast.
I would think you would be fine riding solo and lightly to moderately loaded, even if you like things a little stiffer than me.