TPS, or the Throttle Position Sensor is the device that tells the computer how far the throttle plate is open. The major misconception with this device is that the car uses it for fuel delivery. The MAP (Manifold Air Pressure) or MAF (Mass Air Flow) actually have this job, not the TPS. The job of the TPS is for what is called Power Enrichment in the computer. At a programmed TPS %, the car will resort to a different set Air/Fuel ratio for the added demand on the motor.

The TPS-TEC is supposed to take the real TPS and tell the computer you are at a higher TPS%. This is all done through varying voltage, so the device itself most likely works. However, the real question is "what does it achieve". Well, it achieves what your foot achieves. You can think that your car is faster because instead of 70% throttle, it only takes 60% throttle to go into this Power Enrichment mode.

The other questionable advertising claim is its TPS% change. It claims that 70% throttle is all you need with this device...which is the exact same % that the stock computer is programmed for (at least on automatic 3.1 and 2.8 FWDs) to hit PE mode. It is uncertain if this means 70% of the stock 70%, or if its just the SAME % as stock.

*UPDATE*

I have now tried one of these devices on a 91 Lumina Z34 using freescan to monitor the TPS that the computer sees. It appears that the TPS is the same as it would be stock until you hit 94% real TPS. It immediately jumps to 100. Thats 6% difference at near WOT anyway. What a complete waste of money, it doesn't even do what it advertises!

If you still insist this device gives you better throttle response, its time to have the ass-dyno recalibrated.