Usually I wouldn't want to bring my baby to the mud, but in the last month I've made a couple trips to a friends hunting camp, one with the OEM 20's and one with OEM 18s (as my "winter" wheels in south LA.) The X5 was only limited by ground clearance, but me being the more experienced driver of the 4 of us I was able to go through as much/more than the 4x4 chevy trucks without getting stuck
Now I just need to get my 3 wheeler together before the next trip up there so my baby can stay clean and I'll just take the wheeler to the camp as that road is pretty damn rough!
But if I have to drive it again I will make someone stand on the road with a camcorder to catch us all coming through for some nice entertaining video.