CTS Insight works really well with the 6.0's. It covers: Accel Pedal Position, Barometric Pressure, Battery Voltage, Corrected Speed (03-04), Engine Coolant Temp, Engine Load, Engine Oil Temp, Engine RPM, Engine Run Time, Exh. Backpressure, FICM Voltage, FICM Synchronization, Gear with TCL, ICP Pressure, ICP Voltage, INJ Press Regulator, Injector Pulse Width, Intake Air Temp, Main INJ PWR, Manifold Abs Pressure, Mass Air Flow, Mileage Coach, MPG Instant, MPG Average, TCC Duty Cycle, Time 0-60, Time 1/4 mile, Trans Fluid Temp, Turbo Boost, Vehicle Speed (04-07), Variable Geometry Turbo Duty Cycle.
Only other one I would see being a good monitor would be a Dashdaq XL (same thing as a spartan without the tuning) but I haven't heard of anyone using one on a 6.0. I've got the CTS instock. IM me if your interested. You can also add different PID's to it with individual harness's (egt, boost, coolant temp, etc.)