Okay, first of all, I'm not even a player of Gran Turismo. I will officially become a player (and addict) when my UMD arrives. I've always been the guy admiring the franchise, and wishing for a portable GT.
My point, is that even I understand the fundamental gameplay of Gran Turismo:
1. Start at the bottom
2. Win races, and earn credits
3. Buy your dream car(s)
4. Repeat steps 2 & 3
I'm usually good at reading people. You seem like the person who would prefer Arcade racers, and the person who would use a cheat code to unlock every car on day 1.
Oh, and by the way, for people who don't understand the formula behind Polyphony's crazy idea for limited cars on specific days, well I can explain it. I imagine that PD was considering the audience, gamers who would pick up the game, and put it down again. By having players work for the cars (aka by changing in-game days by competing in races), they are extending the life of the game. Trying to collect over 800 cars is not easy as it is, so by limiting the selection, PD is giving players a longer playtime and making them more involved with the game.
This strategy will also prolong the gameplay until GT5 is released. It makes it harder to buy every car, and then transfer them to GT5. So I do understand this strategy.
Good enough?
Oh and by the way, if you don't want to play the game anymore, send it to me. Someone who actually want's the game.