Cars you win in one-on-one challenges:
Kudos Challenge level 1: Z3 Roadster 3.0i
Kudos Challenge level 2: Boxster S
Kudos Challenge level 3: Focus Cosworth
Kudos Challenge level 5: Skyline GTR
Kudos Challenge level 7: Corvette ZO6
Kudos Challenge level 9: 360 Spider and 360 Modena
Kudos Challenge level 11: Viper RT-10
Kudos Challenge level 12: 911 GT2