AndreasFSC
Too much going on...
If you have unzipped the safety car files to '...Gamedata\Teams\TrackVehicles\Safetycar', open SafetyCar_Alfa_Romeo_156.car and change it from:
//HDVehicle=SafetyCar_Jaguar.hdc
HDVehicle=SafetyCar_Alfa_Romeo_156.hdc
Graphics=SafetyCar_ALFA_ROMEO_156.cas
//Graphics=SafetyCar_Jaguar.cas
to:
HDVehicle=SafetyCar_Jaguar.hdc
//HDVehicle=SafetyCar_Alfa_Romeo_156.hdc
//Graphics=SafetyCar_ALFA_ROMEO_156.cas
Graphics=SafetyCar_Jaguar.cas
Then do the same for the other safety cars, and you should have the Jaguar safety car
//HDVehicle=SafetyCar_Jaguar.hdc
HDVehicle=SafetyCar_Alfa_Romeo_156.hdc
Graphics=SafetyCar_ALFA_ROMEO_156.cas
//Graphics=SafetyCar_Jaguar.cas
to:
HDVehicle=SafetyCar_Jaguar.hdc
//HDVehicle=SafetyCar_Alfa_Romeo_156.hdc
//Graphics=SafetyCar_ALFA_ROMEO_156.cas
Graphics=SafetyCar_Jaguar.cas
Then do the same for the other safety cars, and you should have the Jaguar safety car