Speaking as a drifting n00b, I will tell you what I think are the three most important parts of a drift:
1. Throttle Control
2. Throttle Control
3. See 1 & 2
Seriously. It doesn't matter what you drive...high powered, low powered, whatever. It doesn't matter how much you countersteer. If you're giving it to much throttle, you're gonna spin out. If you give it too little, the rear tires are going to regain traction, and if you're angle is high, you'll get a snap effect that will probably throw you off the road.
It is important to note that you'll probably rarely keep the throttle at the max during the majority of a drift, especially in a high-powered car. The only exception is long, low-angled drifts.
Typically, the only time I have the gas floored is during the entrance to a drift. I enter by slowing down, turning to the outside, then swerving to the inside and flooring the gas. The back tires start spinning and the back end comes out. Time for throttle control! Let up on the gas a bit as you begin countersteering. Don't let up TOO much though, or the back will regain traction, and you'll likely get that snap and spin in the other direction. As you approach the end of the drift, you'll actually RELEASE the throttle (Slowly! But not too slow...) and allow the back to regain traction as you center the wheel.
Throughout your drift, you have to listen to the tires and watch your angle. If your angle is increasing and/or the tires are getting louder and higher pitched, then you have too much throttle. If the car is beginning to travel in a straight line, but the car is still pointing at an angle, then you gave too little throttle and you're probably about to get a snap.
Honestly, I would recommend practicing drifts with a 4WD car. 4WD cars seem to be more forgiving with having the proper amount of countersteer, as long as you don't countersteer too much. But if you don't countersteer enough, then you're less likely to spin out.