I finally got to play Dirt Rally and can tell you its awesome. The stages are tight and difficult. The rear wheel drive E30 M3 was handful and crash damage was pretty cool. You could still drive with a puncture but depending on the corner it would pull or affect the handling differently. The variation in road surface was noticeable too. It was slippery out by the edges and clean with grip where the dirt was hard packed.
The rain felt right. The car slid like a car on a wet surface. Transitions between surfaces felt like you think they would. Even Pikes Peak was properly modeled – like the rock formations looked like they were modeled after photographs from the mountain. The game is awesome!