My 2 cents worth, since I've run P, C, and E load tires on mine.
Keep in mind Michigan literally ranks dead last in the 50 states as far as the condition of our roads. Bent rims and blown out side walls are a common, so much so, that I flat out refuse to own a car, especially with the low profile tires.
So, for me, I replaced the OEM P-rated tire when I did a 2 inch lift, with a set of C-rated 255/70R17 BFG Mud Terrains. With a lift, a taller side wall, and pot holes, the C-rated tire offered some improved stability due to significantly less side wall flex. The ride was only slightly harsher and the fuel economy dropped from 23mpg (overall) down to around 18mpg...partially because of the lift, as well.
My current tires are E-rated, 265/70R17 BFG All-Terrains. It is a heavier tire. Fuel economy dropped to 16.5 overall. Did I need the E-rated tires? NO. It was simply that these happen to be available at the time, and not the C-rated ones. The ride is actually better with the heavier tires, however, I did put on new Bilstein 5100 shocks, FJ Cruiser springs, and Spydertrax wheel spacers...so, a few variables.