RE: What the Best RC drift car?
Here's the scoop, any car can drift, electric is easier to drift, but nitro is fine as well. You'll probably want some decent drift tires, but you can make those yourself.
There's LOADS of best drift car threads on this forum, so next time just read. In fact, there's 3 of these threads on the FRONT PAGE right now.
As for 4WD vs. 2WD, RC drifters are 4WD because it's much easier to control a 4WD car that small. It has to do with grip, weight, and surface, but the point is that you could drift with 2WD (front OR back) as well, it would just be harder.
For full scale drifting, you can drift with RWD, FWD, AWD, 4WD, any of them. RWD is much easier to control while drifting for obvous reasons. 4WD and AWD tend to pull the car around the turn and make it difficult for the rear to slide out. FWD can be used for drifting (there's 2 FWD cars in D1GP) but they tend to drift much slower because they have to use the e-brake much more. RWD is usually used for drifting due to the variety of techniques that you can use to initiate a drift. You can only do certain types of drifting in RWD. Also, it's much easier to have a different wheel speed for front and rear in a 2WD car. The larger the differential, the more angle. This is how clutch kick, braking, power over, and e-brake drifting work.
If you want to know more about how drifting works, go watch the Drift King video, or if you're cheap or lazy go look it up on wikipedia.org.