The Formula GT car appears in the Used Car Dealership randomly. The cars 
available at the UCD are different each day of game time. A day passes when
you complete a race or finish a license test. You can speed up the process 
by loading a license test and advancing to the next test, without ever 
actually doing the test. When the load screen appears between tests, one 
day will have passed. Five game days are required to completely refresh the
Used Car Dealership's current stock, allowing for the chance of another 
Formula GT car to appear.