I simply can't drive without it. Keep using it and it will come to you. I've been using TrackIR for three years now and in the beginning I also had problems with hitting apex while using TIR, but after a while it started to feel real good. Now I feel like I'm trapped in a cage if I don't have it enabled...
Traction and torque is mainly what gives you an ET. Hi-rpm horsepowers will give you top end speed while not affecting your ET all that much, really. Same goes pretty much for aerodynamics Becky (unless your driving a wall, that is)