Easy Way to Not Lose Cars
All you need to do is take out your memory stick before it autosaves on the menu that shows the pinkslip track that you are racing After the race if you win just simply hit options menu go to game and put autosave back on
Extreme nitrous series
To unlock the extreme nitrous series in arcade mode get 100 in career mode
Unlock all Arcade Mode cars and tracks
Go to the Extras menu In there select the Cheats menu Type the below code
Unlockable Arcade Mode Cars and Tracks
Go to the Extras menu then the Cheats menu and enter PIES