The answer to all your code requests.

[georgeymoney]

Download MK's. Download someones garage. Read garage. Change around your slot one car. Right click on the car->List coded car. Use your Gameshark V2 or Codebreaker 4+ to use codes. Do not forget to enable tha master code! Swap discs, and check out your spiffy new ride.

 

[truenodrifter]

would the master could happen to be the same as for normal gt3 cheats? my codebreaker is freezing for some god damned reason.

 

[Mr Chaos]

Yes the normal enable code should work.
FA7A006E 32ABAAE9