You definetely want to leave both ASM and TCS at zero. They are both electronic limiters that prevent the car from doing what you tell it to do. In other words, they're idiot-protection. If you're not an idiot, you don't need them.
ASM - Active Stability Management. Limits power and applies brakes to wheels individually as the car starts to slide, in order to prevent it from doing so. In other words, this is the LAST thing you want if you're drifting.
TCS - Traction Control System. Attempts to prevent the car from spinning out if you give it too much throttle. The main use is for launches (that's why the car is so much faster off the starting line if you have TCS on). However, for drifting, we obviously want to be able to freely control the throttle even when the car is sideways and spinning out already. So this is the second to last thing you want if you're drifting.
The rest is all personal opinion and style, but I can garauntee that you want these both set at zero.
