Originally posted by sjs:
Please understand that I'm not taking shots at you, but when a forum like this is read by people of all knowledge and skill levels, issues related to safety must be debated vigorously by those who feel that the advice given is in error and potentially dangerous.
As well, the original question, "Can anyone explain toe/heel (sic) shifting?" implies spirited driving, and most likely a race track experience. I, personally, don't employ heel-and-toe downshifting during my routine drives around town.
Since a racing scenario was implied, it makes sense that one is not concerned with an icy road.
About the only time I use the engine to brake on a track is if I am entering a corner that requires very little brake input while at high rpm, like the off-camber left-hander after the exit of the Corkscrew at Laguna Seca.