You'll need to load the second Forza disk onto your Xbox 360 to gain access to loads of extras.Forza 3 will offer to install the contents of the second disk onto the Xbox 360’s hard drive automatically when you first start the game, or if storage space is at a premium for you the game will instead offer to install sections of it as required.
The main career disk will contain 300 cars and most of tracks, Turn 10 have wisely decided to group together the remaining 100 cars and a few road-based tracks into packs.
Road Racing Track Pack – 730.4 MB
Rally di Positano
Fujimi Kaido
Nurburgring Nordschleife
Asian Car Pack – 442.6 MB
2000GT
Axela Sport 23S
Civic 1.5 VTi
Civic Si Coupe
Civic Type-R
CR-X Del Sol SiR
Eclipse GSX
Eclipse GTS
Fairlady Z 432
FTO GP Version R
GTO
Impreza 22B STi
Legacy B4 2.0 GT
Mazdaspeed Familia
MINE’s R32 Skyline GT-R
MR2 GT
No 16 G’ZOX NSX
NSX-R
Prelude SiR
Savanna RX-7
Skyline Coupe 350GT
Soarer 430 SCV
Supra 2.0 GT Twin Turbo
Tom’s T020 MR2
Tom’s W123 MR-S
Top Secret 0-300 Supra
No 3 HASEMISPORT Endless Z
No 46 Dream Cube’s ADVAN Z
No 23 XANAVI NISMO GT-R
No 32 NISSAN R390 GT1
No 3 Toyota Motorsports GT-ONE TS020
No 35 YellowHat YMS Supra
No 6 EXXON Superflo Supra R390
No 25 ECLIPSE ADVAN SUPRA
No 23 Nissan Motorsports R390
European Car Pack – 424.8 MB
300SL Gulwing Coupe
9-3 Aero
Beetle
Carlton CC8S
Cerbera Speed 12
CLK55 AMG Coupe GranSport
Delta Integrale EVO
Elan Sprint
Esprit V8
E-type S1
Leon Cupra R
Monaro VXR
No 24 At-Speed S60 R
Stratos HF Stradale
No 8 Audi ABT TT-R
Tuscan S
V12 Vanquish
XJ220
No 4 Johansson Motorsport R8
No 5 Audi Sport Japan Team Goh R8
No 1 Champion S4 Competition
No 7 Team Bentley Speed 8
No 2 BMW Motorsport M3 GTR
No 41 Team McLaren F1 GTR
No 15 BMW Motorsport V12 LMR
No 72 Team Alphand Aventures 550 Maranello GTS
No 12 Risi Competizione F333 SP
No 9 Vitaphone Racing Team MC12
No 5 OPC TEAM PHOENIX Astra V8
No 3 Peugeot Talbot Sport 905 EVO 1C
No 3 Lechner Racing School Team 1 911 GT3 Cup
AMG Mercedes CLK GTR
R8
No 1 Peugeot 207 Super 2000
No 5 Zakspeed Racing 911 GT1-98
No 41 Gulf Team Davidoff McLaren F1 GTR
American Car Pack – 324.8 MB
Cobra 427 S/C
Corvette Grand Sport
Corvette Stingray 427
Corvette ZR-1
CTS-V
G35 Coupe
GT40 MkII
GTO
GTO Hardtop
Integra Type-R
Mustang GT NSX
PT Cruiser GT
Regal GNX
S281
Series 1
SRT4
Stealth R/T Turbo
Eagle Talon TSi Turbo
Viper GTS ACR
No 16 Team Cadillac CTS-V
No 6 Team Cadillac Northstar LMP-02
No 126 Team Zakspeed Viper GTS-R
No 57 Carsport Holland Viper GTS-R
No 11 JML Team Panoz LMP-01
No 26 Konrad Motorsports S7R
No 81 Team LNT Panoz Esperante GTLM
No 91 Viper Team Oreca GTS-R
Source: TheSixthAxis