first buy a turbo car with at least 600hp and enter the tuned turbo catagory in the 'special event' section and enter the second race on the test course track. If you car is fast enough you should win the race. You will get 50k in cash and a free car. The free car is worth 250000cr. So if you sell it you will get 300000cr for an easy race! Repeat this as many times as you want to get easy money! Oh, yeah you might want to keep one of the cars coz its VERY FAST!! have fun!
Once unlocked, go to the endurance races and Race on the Seattle Circuit 100 miles. Win and you have a Ford GT90