Loose is fast.
Not having driven either car, I am guessing, but it sounds like Cory's car is a little more rear biased like mine so you have to have your foot on the gas and drive line engaged when cornering and Kevin's is still a bit more neutral or front biased and needs a kick to rotate.
Left foot braking is a double edged sword. While it keeps the diffs engaged, it can also induce understeer and/or oversteer depending on conditions and brake configuration. Often it is best used before turn initiation to drop speed instead of a lift and shift weight forward. It also doesn't work unless you are good at it! Practice a ton on the street. practicing at autocross or on the track is often detrimental to times.
If you entered a corner near the right speed, throttle steering is often much more effective mid corner as long as you don't do a big lift and unlock everything, unless that is needed.
