I had a similar problem on my FFR. Replaced the throttle cable with the Lokar unit. No problems, but I thought the same thing, I am getting used to the power. But what happened was the pedal had more room than it needed so I was stretching the cable every time I pushed it to the floor.
After adjusting the cable 2 or 3 times, I installed a stop under the pedal. No more problems and I get that same surprise everytime I lay into it.
Later,
Mike