Easy on the EK, i do it on my daily drive to and from work lol. Sets me up nicely for the epic amounts of roundabouts..
i swear you can only do the heel toe thing when in a good car coz i cant do it for **** in mine.
I know its to match the revs so you don't get that lurch into the next gear but
i heard it is used for rear wheel drive cars as if you were to just let up the clutch without matching the revs the rear wheels can ( CHIRP ) so to speak ( as in spin briefly due to the revs climbing suddenly ) which in turn un settles the car for the corner..........
please correct me if i am wrong but i can see the logic to it.
personally i love doing it , feel silly when i get it wrong.
All I know is that technique is used for drifting, not sure how often it is used for normal racing, but its basicly engine braking I think