Complete the following tasks to unlock cars on Challenge Mode.

Car	How to unlock
Audi R8	Complete Audi R8 Challenge.
Bentley EXP Speed 8	Complete Bentley Challenge.
BMW M3 GTR	Complete BMW M3 Challenge.
BMW V12 LMR	Complete BMW V12 Challenge.
Dome S101	Complete Dome Challenge.
Lister LMP	Complete Lister LMP Challenge.
Lister Storm	Complete Lister Storm Challenge.
McLaren F1 GTR	Complete McLaren Challenge.
Panoz Esperante GTR1	Complete Panoz Esperante Challenge.
Panoz LMP-1 Evo	Complete Panoz LMP Challenge.
Pilbeam LMP	Complete Pilbeam Challenge.
Quaife GT1	Complete Quaife Challenge.
Rockingham Champ Car	Complete Rockingham Challenge.
Sintura GTS	Complete Sintura Challenge.
Vemac 320R	Complete Vemac Challenge.