already unlocked

300c
brera
camaro
rx8
mazdaspeed3
clk500
camaron
ccx

proper unlocks

240sx - checkpoint challenge 7.4.2
350z - career unlock
bmw - reward card
carreragt - only exotic (unlocks at end of game)
caymans
challengern
charger06 - only muscle (unlocks at end of game)
charger69
chevelle - offline reward 5
clio
corvettez06
cross - offline reward card
cuda
db9
dumptruck - offline reward
ecipsegt
eclipse - offline reward
elise
fordgt
firetruck - offline reward
gallardo
imprezawrxsti
jaguarxk - collector challenge
lancerevo9
monaro
murcielago
murcielago640 - offline reward
mustanggt
mustangshlbyo - only muscle (unlocks at end of game)
r32 - only tuner (unlocks at end of game)
r8
rx7
skyline - no muscle (unlocks at end of game)
sl65 - only exotic (unlocks at end of game)
slr
supra

missing unlocks

challenger71 - challenge angie_casino
997tt - casino zone 2
corolla - tuner carlot
g35 - tuner carlot
mustangshlbyn - collectors race mustangshlbyo 7.5.3
zonda - collector race 7.5.2

custom entry

t1_exotic_neville -a3 ---> exotic carlot
911turbo ---> casino zone 3
daruis_ai - speedtest ---> darius circuit
hero - bmwm3gtr ---> exotic carlot
demo_vid_gallardo - porsche 997 carrera s ---> casino checkpoint 5.4.1
t1_tuner_neville - mazda3 mps ---> chinatown zone
t1_muscle_neville - cts ---> muscle carlot
cop_gto ----> rewardcard (cop corvette unlocks at endgame)
angie_casinoai - corvette c6 ---> muscle racewar
yumi - audi a3 ---> exotic carlot
kenji_casino - lancer evo 8 ---> tuner racewar
wrx_red - golf gti ---> tuner carlot
rival_kenji - rx8speedt ---> mazda dealer carlot

online unlocks

is300 - challenge is300
roadrunner - challenge roadrunner
europa - challenge europa
gto - muscle race wars
997gt3rs - casino zone 1
mr2 - drift challenge mr2

traffic unlock

cs_semi, trafha, trafminivan, trafgarb, trafcemtr, trafpickupvan, traftaxi - dumptruck challenge series