Save your game, save your savegame to a usb ,(take the usb out of ps3) start up gt5 , send the car, color ,suit etc etc , to your second account, ( if you dont have 1 extra make one extra) , quit gt5 , load your save back to your ps3 from the usb , and you see you have your ( for example) car back , and that same car is in your second account, thats it