If you are doing it in A-spec mode be sure to have a decent amount of quiet time available. In order to do complete this event your Formula Gran Turismo car must be properly tuned to the way you drive. Aerodynamics, suspension and brake balance are a must.
Also if you have an FGT and already been using it, chances are you'll need two things as well: An oil change and an engine rebuild. You'd be surprised how much HP you lose on the FGT with a bad oil condition and an engine that has a few hundred miles on it. And since this a "same car" race, you'll need every horsepower you can get.
Good luck and remember to bash the living heck outta those AI zombies. Whatever you can to ensure your win.