http://iphong.com/upload/drifting.mov
Here is another drifting video.
First U need AWD ... this is a must for Xmods, I've never succeed drifting with AWD, and FWD never drifts. Then U need a smooth surface with no bump in order for the car to slide. Locking diff is not a must but you should, the car will handle better. What I did was I used super glue, with this method, It will not be unlockable (You need a to purchase a new diff in case), but I didn't regret, it improved performance.
Drifting... Ok, it takes a lots of practice. Don't let the car goes too fast, you will easily lose control. In real life drifting, a professional drifters never approach turns and drift at high speed, so do you? That's the reason why you always lose control and the car spins even you do immediate counter steering. Let it goes slow first then when you want to drift, pull the trigger, the car will drift. when the car starts to drift,release the trigger halfway (don't release completely, the car will stops) counter steer then pull the trigger again. This way, you will be able to control the car.
People always say, more torque = easier drifting. For me, I don't think so, 8T Pinion and 23T Spur has too much torque, it accelerates too quick = easier to lose control. What I did was I used 11T pinion instead, I found this very useful and easier to control.
Enjoy!