I thought RR6 was the opposite, the drifting in RR6 seems alot more strict then the PSP version to me, its still auto pilot around corners, but the punishment for needless drifting is alot higher, and you've got to actually exit drifts this time which isnt always that easy to do.
The PSP version i used nothing but DYN cars and constant drifting working perfectly, in RR6 that method led to loosing alot of speed after turns and just not being able to keep up.
I think the drifting method in both games is pretty crap and it makes the whole thing feel like you're on some sort of rollercoaster around bends then an actual racetrack. The game gets much harder much quicker then RR PSP too, which IMO was piss easy outside of the horrid max tours.
Although really the difficult RR6 levels are just more frustrating then anything, any race which is just dependant on a boring 3 lap race where only the last 30 seconds of boost matter sucks in general. I hate those races, might as well make then one lap.