Great points from everyone!
GaryS: that is very interesting info. Based on that, my gut feeling is to reduce the tire pressures a little bit to soak up a few more bumps and then leave the rest to the suspension.
I agree that it's hard to say for sure what will work best, aside from trial and error as most people have stated. That said, I got a loaner with 17-inch low-performance RFTs and non-sport pack, and DAMN, the FSDs with 18-inch wheels and high-performance tires are MUCH more comfy.
So yes, this question is a little silly in the sense that it's about fine-tuning from one good situation to an even better one.