well i have got this thing driving straight but will kick into a drift without any difficulty.. this car is a lot more stable that anything I have tried before due to very stiff suspension (which was always a bit buggy / glitchy but have got it rock solid.
also used xbox controller in this vid which works great and allows holding a clean drift without too much key tapping. also a big feature is partial throttle with a controller.. as opposed to keyboard..
tbh.. as you already know from your work on this kinda thing.. it probably needs a few setups.. one for keys.. one for wheel/controller etc
worth remembering that bf42 was built on the Rally Sport Challenge engine.. and so when the cars are setup for racing like this they really are damn good.