Actually, in the WRC the "car" is the same. That said, it is a different engine tuning, different transmission, different suspension arms, different brakes, different wheels and tires, different dampers, etc. so you can decide whether you think the car is the same car. It is the same shell, though. In the early 90s, some of the WRC rounds were gravel one day and pavement the next. The teams would completely strip the cars and rebuild them overnight. They made rules that make entire rallies a consistent surface to try to bring the cost down...among other reasons.
Our championship has less than 12 paved miles of the couple thousand total stage miles. When we run a paved stage or part of a stage, it is usually grouped with a gravel stage and that means we are on gravel setup.
The above picture was taken at Waterford Hills Raceway, a roadracing facility in MI. It was a Solo event...just one car at a time for fun. I decided the night before at midnight that i would go, so I loaded up in the morning and changed the tires to my sticky tarmac tires at the track. I did no changes to the car. Didn't even drop the coilovers.
Now I have highly adjustable shocks and plan to baseline a workable tarmac setup by twisting knobs so that I can optimise the car on those few stages with a quick adjustment, but not more than that. I may play with ride height and swaybar settings for fun, but I usually don't get a chance to mess with it in a rally. Besides, by leaving it high I can get the crowd going by jumping curbs as I am doing above!
Eric