What kind of mileage are you getting? I have a qudratrac and a 4.0 and I'm getting in the low 20's on the highway at 70. Have you changed fuel filter? (Non Autozone) and upgraded Bosch 4-hole injectors?
I think the jeep 4x4 system is totally pimp, seeing as how it is capable of 4x4 and 4x2 on-demand. Not many systems can operate like that.