I wrote this on the other forum, but I'll put most of it here and add a little bit.
It does help with throttle response, but not with lag.
Terms matter, specifically how "lag" is defined.
By my definition, lag is the time between the driver pressing the gas pedal and the engine responding.
By that definition, the TKO unit does NOT affect lag in any way, shape, or form. There isn't even an argument - it is an objective fact.
I'm making that bold statement because I don't want anyone to get the impression that it does and end up wasting their money like I did.
The lag is a function of the PCM's programming. The TKO unit does not alter the PCM's calibration, and by that fact alone I can stand by my assertion that it does not affect the lag.
Lag is also somewhat affected by the mass of the clutch (flywheel + pressure plate) - switching to a lighter weight assembly does help, but that base amount of lag is still there.
It is most noticeable off idle. With the engine idling, stab the gas pedal and take note of how long it takes the engine to actually respond. Some have guessed it's on the order of 200-300 msec, possibly more. You can adjust the TKO throttle response knob to 100% and that lag will still be there.
The only way to change the amount of lag is by changing the PCM calibration. It can't be done with HPTuners without throwing the car into limp mode. The Prefix PCM is supposed to help, but I have no way of verifying.
Many of us wanted to eliminate the lag, hence the disappointment.
All the TKO unit does it modify the voltage coming from the gas pedal. Set it at 0 and it does nothing. Set it at 100 and a small input on the gas pedal will now read as WOT voltage-wise on the output side (which goes directly to the PCM). It effectively reduces the resolution of the gas pedal, giving the illusion of better throttle response. I guess it is technically more than an illusion, because it basically makes small gas pedal inputs look like large ones, but that's also where the danger lies...if you try to pedal your way out of a wheel spin situation with the TKO unit set high, you have to be VERY light on the pedal or you'll find yourself in a pilot induced oscillation state (i.e. huge swings in voltage over a very short period of time). That happened to me once, and I almost lost control of my car because of it. I removed it shortly thereafter, and I will never reinstall it. I can't even imagine trying to get a good launch at the drag strip with it installed.
There are plenty of folks out there that rave about it, but I'm no longer one of them. In my opinion, it is an accident waiting to happen.
Having fine control over the throttle input is a good thing.