I went to the pedalbox website again and read more about the product... saw one of the chart they post and I have an idea on how does it work but I am not sure is it necessary for a street car.
Basically it's a module that allow the driver to adjust what's called... the
"Throttle-Curve"
It alters the values between the actual-throttle-position and the ECU-throttle-position.
Therefore, when the gas pedal is 50% depress and ECU might thought it's at 60% or 70%.
By reading its diagram, the adjustment is most effective through the mid-range.
I am not sure how much it can improve/correct the problem that Mr.kenchan is experience since he is complaining the initial throttle-response.
Which...the pedalbox has the minimum effect on that position.
My opinion, this module is more suitable for track use since the driver can:
1) Adjust the throttle-response according to different track lay-out.
2) weather condition (dry/high traction surface more responsive vs wet/low traction less responsive)
On top of that, I am wondering the adjustment will lose its "effectiveness", not from the device itself, but the driver itself will get used to responsiveness of the throttle.
alcheng's conclusion: Save the $499.
CAD$0.02