Omnipotent goku: I wouldn't get too excited about this. I doubt that Chevy put a real strain guage or anything like that into the SSR driveline.
In theory at least, you can probably get all the raw numerical inputs you need to "calculate" current torque being applied by the engine, from the powertrain control module (PCM) or Vehicle Control Module (VCM) as it more fashionable to call it now.
I say this because there is a capability built into the VCM called "Torque Management". The purpose of that capability is to not allow the driver, engine, torque converter, or transmission to transmit potentially destructive levels of torque to the driveline.
Those potentially destructive levels of torque are rather easily generated by a number of reasonably forseeable occurences or possibilities: a dragstrip tpye launch, torque converter torque multiplication, shifting that has been adjusted too "short" or too "quick", excessive trailer weight, etc.
GM takes programming steps within the VCM to protect the driveline from these kinds of abusive loads. (Yes, this is why the SSR won't lay rubber until you use a microtuner to compromise this protection a bit at your peril). To do so, the VCM apparently has the built-in capability to calculate current torque being generated by the engine, as there are editable fields within the VCM designed to see and limit that torque.
I'm sure GM just tapped into a suitable data field, and then applied an algorithm to convert to human readable value.
The only value I can see in having that center guage, similar to the Gallons per hour guage on the 03 and 04 SSRs, is that it gives you an idea of the actual loading you are subjecting your SSR to under steady state conditions.
If you are thinking that you will take a flash reading off it visually while under hard acceleration and happily report the results here as "MY SSR makes two million ft lb of torque as verified by my torque guage", forget it because:
1. This is a calculated value whose algorithm doesn't necessarily have much to do with gross of net engine torque that a dyno would measure, and
2. The calibration of the guage is, charitably, "coarse", and
2. If you are looking at the guage under hard acceleration, who is looking through the windshield at the ROAD?