This is the wiki:
http://gran-turismo.wikia.com/wiki/Vision_Gran_Turismo_Trophy
I dont buy these cars as I dont want to waste a million so I used my free ones.
I did these ages ago with the Infiniti VGT and the Iso Rivolta.
The Rivolta is a shoe in as its quite powerful.
LOoking that list I feel like more than half a have a good chance... of course dont bother with the Copen Clubman Viziv.
I Have both the VW Golf VGTs and they hammer surprising hard... the 4wd system malkes it easy.
I would imagine the Audi and Fittipaldi would eat everything else alive.
I have the EF7 - I wasted a million on it. I dont have the Audi but I have the Gr.1 and its nice. I also do recall some of them are automatic only so that kills any joy I would have and some have no dash - again, dont buy these.
If you're talking about the other VGT event thats with the super high power cars then its the McLaren VGT all day long.
I have both and they dominiate the Group X and Gr.1 classes however they arent the easiest cars to drive.
The McLarens are my "go to" cars even Gr.X or Gr.1 events are called for however they are both dizzyingly fast to drive. They even drop the hell out of the base Tomahawks.