I just noticed an add on EBay for the Power Chip from SpeedTuningUSA. Has anyone used this option. They re-flash the ECM and add 100HP and 200lbs Tq. Comes with 2 year warantee and this upgrade is not detectable with normal scanners. It is only available for the LB7

Duramax Power Chip: Now available Chevy Duramax Power Chip for all 6.6l Chevy Turbo Diesel engines.
Includes the installation of the Power Chip in the ECU, for all Chevrolet Duramax 6600 V8 Diesel engines. Increase your performance and efficiency with a Power Chip from SpeedTuning®. Up to plus 100HP and 200lbft torque at the wheels. Beats other tuning kits like the Edge Juice Box in performance, drivability and response. With the Duramax Power Chip from SpeedTuning® you don't just interfere the signals to the injection pump, but modify the mapping for injection, boost and timing direct in the control unit. 2 year warranty on the Power Chip. Not detectable with common diagnostics (warranty!).

I'd like to see their claims backed up myself. My money is on the Edge Box