I was able to go thru the Pro FF series quite easily with a fully decked out Vitz.
Not the FASTEST ff car in the game, but I was able to lap all the cars at Cote... including the Beetle Cup car and Spoon Civic.
Like I said, not the fastest car in the game, but then again the AI ain't the best drivers.
See my Vitz Pro write-up for settings if interested.