It´s from Rob Wilson. He´s a driver coach and has coached thousands of drivers through the years. Half the drivers on the grid today. He doesn´t look like much but looks can be deceiving. Anyway, he´s trained Lewis and Kimi and it was interesting what he said about the two guys. He´s trained Maldonado and Senna as well as mentioned in the article below. I suggest reading all of it but i bolded the Kimi/Lewis part. I think you have to read it all to get an understanding of the test they did. It´s been translated from Croatian to English and this is one comment from F1T regarding other drivers in F1. He´s absolutely terrific to listen to as well when he breaks down different driving styles on certain tracks like Canada with Lewis and Button. He usually guests The Flying Lap on youtube which i recommend anyone to watch.