Check out his page for what the ECU flash actually does.
actually, his site left me with a lot of questions as to exactly what is being done to the ECU. not go to into specifics here since this has been a hot issue with some in the past and lot of misunderstandings, but here is a direct quote from Ivan on a different site that offers more insight as to what he is doing (the following is in regards to his work on a Bolt):
"Yes there is a noticeable power increase, but that's the easy part.
There is also a noticeable reduction in vibration throughout the rpm range, as well as a marked improvement in throttle sensitivity. (a little goes a longer way)
There is no popping at all on decel and none at re-application of the throttle at any rpm on my bike. Re-application of the throttle is is very smooth and easy to modulate at any rpm.... a much more "direct" feel.
I may not leave the rev-limit at 6000 rpm...
I may drop it down to 5750 because 6000 rpm puts piston speed at slightly over 4600 FPM, and 5750 is appx. 4450 FPM.
I feel that better safe than sorry later. This bike is already set at 5750 (in the lower gears only) already from the factory."