The IT industry is still fairly sucky atm
much to my disgust
I actually considered changing to mechanics myself a year or so ago during an extended unemployment period, but couldn't handle the idea of 4 years of fairly ordinary pay....
That said, I think a mechanic with a good business mind could make an absolute fortune ( perhaps you could specialise in Ford Performance tuning ? :) ). Seriously - a performance tuning house I think should make a fairly good business ( god knows we need more of them in 'Sydney - Land of the Missing Ford Mechanic")
Oh - forgot to say, I think you will learn everything you need to in an apprenticeship. Existing knowledge would probably help to start with, but strong enthusiasm / interest and commitment will make the difference in the long run . . .