That Citroen Xsara rallycross car was insane; how come those (rallycross) cars have so much more power than WRC machines???
WRC cars are forced to user air restrictors to limit the power to about 300 HP. In rallycross I think there are no such restrictors (or they are bigger). And rallycross races are shorter than rallies, so the engines don't have to last as long between revisions/rebuilds.