Personally, I love the McLaren F1. I have a streetcar version of it on my shelf as a scale car. I would love to see many variations of this race car. I STILL think it is the most powerful car in the world (from my "McLaren F1 vs. Ferrari Enzo" topic).
The most notable is the Gulf McLaren F1. They don't get this one in, they're missing out on a popular McLaren. And if they don't get it in the game, that would be like not putting the Tennssee Volunteers in the next NCAA Football game.
Come on, PD! By the way, the McLaren should be the ultimate car to any garage. If you can't own one in real life, you can sure as hell get one in the game. Thank those incredible Japanese and non-Japanese working on Gran Turismo 4, folks. They will give you a great game that you may need to take extended vacations for. Just hope you get paid vacation, though...