"e-brake" generally means the engine brake, which is when you downshift to slow yourself down (big 18-wheelers use this because the normal brakes aren't good enough). I think they mean the handbrake, which is generally space bar.
After lots of practice, I finally beat the drifting race in the GRID demo. FREAKEN HARD!!!
the idea is to keep your car sliding down the entire track, and you have to get as close as you can to the cones on the insides of the corners. Every two turns or so, you get another number added to your multiplier, and you can get up to 20,000 points for a perfect drift (very close to the cone).
Practice makes perfect.