Johnston Research And Performance (JRP) has hooked me up with the new Sprint Booster v.3 to test. I was skeptical at first, but I discovered that I really like it. The super fast throttle response is very welcome in a drive-by-wire car. Downshifts are where it will make the most difference for me on the track. I also test the valet mode and pedal lock mode.
You can get one at sprintboosterusa.com
To clarify, this device amplifies the signal of the throttle pedal, allowing you to get to full throttle quicker.