I think that we can conclude all that tech stuff withe very simple sentence. We need to put S2000 cars in separate class like N4+ for example. Then there is no need to compare those two cars and no need to equalize their performance. We, in this forum know that S2000 cars and Imprezas and Evos are completely different cars but normal crowds do not care about it.
We could read that Tänak was 4th and 5th in GrN in Portugal and some sources also mentioned that he was first in traditional GrN category. Normal reader, spectator do not care that those cars are different cars. Average spectator can understand that WRC car is something different, then there is GrN and 2WD category and that is all. If we can divide those two cars in different categories then maybe there are more people who can understand that those cars are not equal.
A long as they are not in different classes, those who drive with traditional GrN cars will be shaded big time.