I think it is that split second, when you throw your weight and hit the throttle. Your just about to go for a digger waiting for the sled to catch up with your body weight. Hopefully it does!
What I have found in testing between my Cat turbo and my Ski-Doo turbos is the response is much better with the Ski-Doo. I feel this is due to the shift force generated by the TRA in the initail part of the shift curve. Response is right now. So much so that I'm thinking about putting a TRA on my Cat to try. My XP turbo will make about 3-4 pounds of boost with the track in the air with no load on it, just wicking the throttle. The Cat won't build boost even if some brake is applied.
its like when you were a bad kid and the old man was coming after you with the belt, you knew it was coming, it wouldn't magically go away then it would hit you wham.!
Drive/Ride a Supercharger and you will easly se the difference between lag and boost. However stay on the throttle and watch the turbo take center stage and the supercharger fade away.