Before the deathblow is given to this thread, yeah. Any car not there in Arcade Mode you must earn in Gran Turismo Mode. Even if you end up selling the car in GT Mode, it will be forever unlocked in Arcade Mode unless your GT file gets corrupted, you delete your GT game file, or whatever. I'm kind of just buying cars in GT Mode just to unlock them in Arcade Mode. Most recent thing I unlocked was the Hyundai Clix. I don't like its looks, but sadly, it'll be there for me to race again and again if I wanted to in Arcade Mode.