Don't even bother with co driver - although the 7 right/left lets me know to floor it right through the corner.
Use your mini map, son. If you're using 345 HP STIs/Evos and slick tires for tarmac and respective tires for snow and gravel, shouldn't be hard at all. Make sure traction control is completely off. Not even 1, I mean OFF.
Just brake early and you'll have them 3-5 seconds ahead of the game, easy.