sorry to disappoint you, but, you are talking about an icon you can only find on Mario Kart ds.
Do ALOT of races do the Grand Prix and othre missions to unlock new ones.
you have to complete all of the grand prix levels (passing them obviously) and do all missions x Hope this helped ;)
how to unlock missions in gta sanandreas
complete the missions
beat some missions and then u will unlock 1 by 1
Win 1st place in every Grand prix in every class (50cc, 100cc, 150cc, etc), complete all the missions. By doing this you will have unlocked every cart and grand prix and then you have completed it
win grand prix's
Pass all the missions.
complet a grand pics race
You have to unlock it in Grand Prix or something.
Get gold trophy in grand prixs to unlock karts and characters.
No, you will have a Story Complete after you finish all the main missions that tells you that you have completed all of the missions.