I found the E36 a good car actually, i can drift perfect corners with it, running about 500bhp. you get an achievement for 100,000 drift points in 1 lap! other good cars are nissan silvia's/200sx as they are well balanced - the reason they are used in real life alot, ive been in my friends s14a whilst drifting at a track day and they are good. Rx-7's are good as they have plenty of power but lack a bit in torque due to the rotary engine, so it drifts but doesn't go round in cirlces all the time.
You will need to tune aswell for best results, for example setting gear ratios and stiffening rear suspension more than front, widening front tires more than the rear ( i found this works), and lowering tire pressure and putting in an LSD. also don't go mad and mod to 800bhp because its too much torque and you will just spin out. i find that N/A engines work best aswell as long as their tuned.
also turn off TCS, STM and ABS.