The GM version of the nGauge comes packed with features that include:
-Flash the ECM with HP Tuners files
-Live data scanning and logging ability
-Two analog inputs
This pairs great with the DSX Tuning Fuel Pressure adapter kit!
These marry to the vehicle once a file is flashed. They can be unmarried with a special file. The first three unmarry files are free.
These are not able to flash 17+ model year GM, but they are still usable as a scan/data display device.