I remember taking on the Muscle Car races with a quite-modded Subaru 360, and getting either 1st or 2nd places.
Of course, there's too many wide-open events calling for ~591hp, when 200-250 will do.
Run some if these events with Simulation tires, and suddenly...these races are a lot more difficult; you might want the extra horsepower! The physics model becomes a lot like GT4's.