If you are not 100% confident when going fast, just give up and save your money RE instructors! You will simply never be fast. Personally, this is my case-my problem and that's why I don't put the car on the track much or at all really. I am petrified going at over 160km/hr in 'any' 2-4 seats car higher than 100cm. And the fear gets much worst when I'm in the passenger seat
However, if you are 100% confident, understand apex entries and exit momentums (e.g. blood racer), fine with inertia, and a little crazy but smart.... then I promisse you'll bring all the Cups home mate
RE instructors, sorry mate but those are for the wifes (second-drivers)