I feel the dirt physics are much less accurate than GT's simulation on asphalt. Certainly because the driving model seems to be more correct when the tyres are in contact with the road surface, while being a lot more inaccurate when there's no contact, which is of course the case while rallying for more of the time due to road unevenness. The simulation of tyres digging in and actually gaining grip is also limited. All in all I'd say it feels a bit more arcadey than asphalt driving, but it's still fun to throw around any of the Group B rallycars once in a while.