For us the IFS is a challenge to keep alive off-road, but the back is even more important for strength and needs fabulous wheel travel to make up for the limited front IFS travel. Production IFS/IRS combo 4x4's are simply not practical for hard wheeling. Forest and Desert tracks, sure, but not trail riding, rock crawling, ect. Folks make IFS/IRS buggies, but those designs would not work in a production vehicle. Even a Hummers huge A-arms have little travel and common failures.