When i watch the fast drivers on onboard camera i never see them drifting, though it's fun of course.This means you need to power your way through corners by finding the point where you can keep "drifting" while controlling your turn.
http://www.simracingworld.com/content/279-gtr-quicksetup-guide/Q) "The car snaps away when I accelerate out of a corner"
Try adjusting the differential power locking or increasing the preload. If that doesn't help, revert to the old setting and try reducing the rear bump damping. Alternatively try increasing the rear toe-in but don't exceed +0.5 degrees.