I think it's more a case of getting used to the handling of different cars and becoming better as a driver the more you play it.
Not that the difficulty is based on your Exp. level.
I dont agree with that only because of some of the rally stages where I hadnt even bought/won had a Citreon C4 I think, or done the course etc apart from there, so I wasnt used to driving it in any way shape or form
Either way others have mentioned it, and it seems to fit other particular races also (although the rally ones stick out most)
The constant zooming in and out (right in your central vision) of the rally course in the Special Events is really bugging me (Ive only noticed in Advanced, but its in alll three surface types at this level) - its really distracting