THe biggest key to this car, isn't the suspension set-up. It's the brakes. With the C12s, you're carrying significant weight, and considerable speed. When combined with the balsa wood brakes that it has you've got to plan on stopping 3 times earlier than you normally do.
I recently redid the Italian Avant Garde, then submitted the Write-up for people to review. take a read thorugh it, and this might give you a bit more insight than the previous posters have given.
The Race version of this car is exceptional. A hidden gem in the game.